Need GM guru for 1996 vortec engine help.

have had a problem only in winter where it misses and backfires. The longer I drive the better it gets. Over the last two years I have replaced plugs, rotor, cap, coil, ignition module checked numberous times, lower and upper intake replaced, new fuel injectors, new fuel pump and filter, new CKP sensor, etc. It seems to happen only at part throttle. Driving it ?hard? I don?t have much of a problem.

I assume this is ok. MAF shows around 9 grams/sec at idle which my Haynes manual says is ok. O2 sensors show they are switching rapidly from 100 to 850 mv.

high fuel trims are at cruising. Letting off the accelerator and coasting they go down to single digits or zero.

I should be looking for.

voltmeter test with it last year. I think it checked for reference voltage and for ohms but don?t remember. Anyway they tested good. (According to Haynes manual).

appropriately according in terms of beign close to the guage on my truck. When the truck acted up over the weekend, I pulled over and unplugged the ECT sensor. It made no difference in the missing.

Multiple cylinder misfire code.

drilled a hole in the bottom of the cat, took a screwdriver to ?mash? all the insides of the cat and sucked it out with a shop vac. (Basically hollowed it out). Of course, I still have the code but my hope was to fix the problem if it was a blocked converter. I have never done anything with the converter on bank one.

Actually, a couple of times it would not start. Once it would start would barely idle but once warmed up it would act normal.

brake booster. Actually after fixing this is when it was hard to start.

me where to go from here and if there is a way with my scanner reading to rule out the map sensor?

If it's a plastic intake, it could easily be intake gaskets. It could also be a coking problem - a carbon buildup on the intake, heads, or valves. The carbon absorbs the fuel, leaning out the mixture on a cold start.

You can also try running regular gas instead of premium for hard starting, but that's mostly to help otherwise properly running engines. Your problems sound too substantial for gas volatility to make any difference.

ars have had a problem only in winter where it misses and backfires. The lo nger I drive the better it gets. Over the last two years I have replaced pl ugs, rotor, cap, coil, ignition module checked numberous times, lower and u pper intake replaced, new fuel injectors, new fuel pump and filter, new CKP sensor, etc. It seems to happen only at part throttle. Driving it ?hard ? I don?t have much of a problem.

emp so I assume this is ok. MAF shows around 9 grams/sec at idle which my H aynes manual says is ok. O2 sensors show they are switching rapidly from 10

1. The high fuel trims are at cruising. Letting off the accelerator and co asting they go down to single digits or zero.

range I should be looking for.

a voltmeter test with it last year. I think it checked for reference volta ge and for ohms but don?t remember. Anyway they tested good. (According t o Haynes manual).

g appropriately according in terms of beign close to the guage on my truck. When the truck acted up over the weekend, I pulled over and unplugged the ECT sensor. It made no difference in the missing.

the Multiple cylinder misfire code.

sically drilled a hole in the bottom of the cat, took a screwdriver to ?m ash? all the insides of the cat and sucked it out with a shop vac. (Basic ally hollowed it out). Of course, I still have the code but my hope was to fix the problem if it was a blocked converter. I have never done anything w ith the converter on bank one.

. Actually, a couple of times it would not start. Once it would start would barely idle but once warmed up it would act normal.

power brake booster. Actually after fixing this is when it was hard to sta rt.

e tell me where to go from here and if there is a way with my scanner readi ng to rule out the map sensor?

have had a problem only in winter where it misses and backfires. The longer I drive the better it gets. Over the last two years I have replaced plugs, rotor, cap, coil, ignition module checked numberous times, lower and upper intake replaced, new fuel injectors, new fuel pump and filter, new CKP sensor, etc. It seems to happen only at part throttle. Driving it ?hard? I don?t have much of a problem.

I assume this is ok. MAF shows around 9 grams/sec at idle which my Haynes manual says is ok. O2 sensors show they are switching rapidly from 100 to 850 mv.

The high fuel trims are at cruising. Letting off the accelerator and coasting they go down to single digits or zero.

I should be looking for.

voltmeter test with it last year. I think it checked for reference voltage and for ohms but don?t remember. Anyway they tested good. (According to Haynes manual).

appropriately according in terms of beign close to the guage on my truck. When the truck acted up over the weekend, I pulled over and unplugged the ECT sensor. It made no difference in the missing.

Multiple cylinder misfire code.

basically drilled a hole in the bottom of the cat, took a screwdriver to ?mash? all the insides of the cat and sucked it out with a shop vac. (Basically hollowed it out). Of course, I still have the code but my hope was to fix the problem if it was a blocked converter. I have never done anything with the converter on bank one.

Actually, a couple of times it would not start. Once it would start would barely idle but once warmed up it would act normal.

brake booster. Actually after fixing this is when it was hard to start.

me where to go from here and if there is a way with my scanner reading to rule out the map sensor?

One thing I forgot is the injectors. Is this multi port or throttle body injection? They might need cleaning or replacement.

e been replaced recently.

ears have had a problem only in winter where it misses and backfires. The l onger I drive the better it gets. Over the last two years I have replaced p lugs, rotor, cap, coil, ignition module checked numberous times, lower and upper intake replaced, new fuel injectors, new fuel pump and filter, new CK P sensor, etc. It seems to happen only at part throttle. Driving it ?hard ? I don?t have much of a problem.

temp so I assume this is ok. MAF shows around 9 grams/sec at idle which my Haynes manual says is ok. O2 sensors show they are switching rapidly from 1

k 2. The high fuel trims are at cruising. Letting off the accelerator and c oasting they go down to single digits or zero.

t range I should be looking for.

o a voltmeter test with it last year. I think it checked for reference volt age and for ohms but don?t remember. Anyway they tested good. (According to Haynes manual).

ng appropriately according in terms of beign close to the guage on my truck . When the truck acted up over the weekend, I pulled over and unplugged the ECT sensor. It made no difference in the missing.

t the Multiple cylinder misfire code.

asically drilled a hole in the bottom of the cat, took a screwdriver to ? mash? all the insides of the cat and sucked it out with a shop vac. (Basi cally hollowed it out). Of course, I still have the code but my hope was to fix the problem if it was a blocked converter. I have never done anything with the converter on bank one.

r. Actually, a couple of times it would not start. Once it would start woul d barely idle but once warmed up it would act normal.

e power brake booster. Actually after fixing this is when it was hard to st art.

ne tell me where to go from here and if there is a way with my scanner read ing to rule out the map sensor?

rs have had a problem only in winter where it misses and backfires. The lon ger I drive the better it gets. Over the last two years I have replaced plu gs, rotor, cap, coil, ignition module checked numberous times, lower and up per intake replaced, new fuel injectors, new fuel pump and filter, new CKP sensor, etc. It seems to happen only at part throttle. Driving it ?hard ? I don?t have much of a problem.

mp so I assume this is ok. MAF shows around 9 grams/sec at idle which my Ha ynes manual says is ok. O2 sensors show they are switching rapidly from 100 to 850 mv.

1. The high fuel trims are at cruising. Letting off the accelerator and coa sting they go down to single digits or zero.

range I should be looking for.

a voltmeter test with it last year. I think it checked for reference voltag e and for ohms but don?t remember. Anyway they tested good. (According to Haynes manual).

appropriately according in terms of beign close to the guage on my truck. When the truck acted up over the weekend, I pulled over and unplugged the E CT sensor. It made no difference in the missing.

the Multiple cylinder misfire code.

ically drilled a hole in the bottom of the cat, took a screwdriver to ?ma sh? all the insides of the cat and sucked it out with a shop vac. (Basica lly hollowed it out). Of course, I still have the code but my hope was to f ix the problem if it was a blocked converter. I have never done anything wi th the converter on bank one.

Actually, a couple of times it would not start. Once it would start would barely idle but once warmed up it would act normal.

power brake booster. Actually after fixing this is when it was hard to star t.

tell me where to go from here and if there is a way with my scanner readin g to rule out the map sensor?

Any chance of a clogged or carboned up EGR valve?

ears have had a problem only in winter where it misses and backfires. The l onger I drive the better it gets. Over the last two years I have replaced p lugs, rotor, cap, coil, ignition module checked numberous times, lower and upper intake replaced, new fuel injectors, new fuel pump and filter, new CK P sensor, etc. It seems to happen only at part throttle. Driving it ?hard ? I don?t have much of a problem.

rtec? I know it is electronic. Not sure if it is servicable. I know I dont have an egr code.

temp so I assume this is ok. MAF shows around 9 grams/sec at idle which my Haynes manual says is ok. O2 sensors show they are switching rapidly from 1

k 2. The high fuel trims are at cruising. Letting off the accelerator and c oasting they go down to single digits or zero.

t range I should be looking for.

o a voltmeter test with it last year. I think it checked for reference volt age and for ohms but don?t remember. Anyway they tested good. (According to Haynes manual).

ng appropriately according in terms of beign close to the guage on my truck . When the truck acted up over the weekend, I pulled over and unplugged the ECT sensor. It made no difference in the missing.

t the Multiple cylinder misfire code.

asically drilled a hole in the bottom of the cat, took a screwdriver to ? mash? all the insides of the cat and sucked it out with a shop vac. (Basi cally hollowed it out). Of course, I still have the code but my hope was to fix the problem if it was a blocked converter. I have never done anything with the converter on bank one.

r. Actually, a couple of times it would not start. Once it would start woul d barely idle but once warmed up it would act normal.

e power brake booster. Actually after fixing this is when it was hard to st art.

ne tell me where to go from here and if there is a way with my scanner read ing to rule out the map sensor?

years have had a problem only in winter where it misses and backfires. The longer I drive the better it gets. Over the last two years I have replaced plugs, rotor, cap, coil, ignition module checked numberous times, lower an d upper intake replaced, new fuel injectors, new fuel pump and filter, new CKP sensor, etc. It seems to happen only at part throttle. Driving it ?ha rd? I don?t have much of a problem.

vortec? I know it is electronic. Not sure if it is servicable. I know I don t have an egr code.

t temp so I assume this is ok. MAF shows around 9 grams/sec at idle which m y Haynes manual says is ok. O2 sensors show they are switching rapidly from 100 to 850 mv.

ank 2. The high fuel trims are at cruising. Letting off the accelerator and coasting they go down to single digits or zero.

hat range I should be looking for.

do a voltmeter test with it last year. I think it checked for reference vo ltage and for ohms but don?t remember. Anyway they tested good. (Accordin g to Haynes manual).

ting appropriately according in terms of beign close to the guage on my tru ck. When the truck acted up over the weekend, I pulled over and unplugged t he ECT sensor. It made no difference in the missing.

get the Multiple cylinder misfire code.

basically drilled a hole in the bottom of the cat, took a screwdriver to ?mash? all the insides of the cat and sucked it out with a shop vac. (B asically hollowed it out). Of course, I still have the code but my hope was to fix the problem if it was a blocked converter. I have never done anythi ng with the converter on bank one.

ear. Actually, a couple of times it would not start. Once it would start wo uld barely idle but once warmed up it would act normal.

the power brake booster. Actually after fixing this is when it was hard to start.

yone tell me where to go from here and if there is a way with my scanner re ading to rule out the map sensor?

Been a few years since I worked on one of these but iirc, it's center of th e engine, on top. just to the left of the thermostsat/heater hose entering the engine.

have had a problem only in winter where it misses and backfires. The longer I drive the better it gets. Over the last two years I have replaced plugs, rotor, cap, coil, ignition module checked numberous times, lower and upper intake replaced, new fuel injectors, new fuel pump and filter, new CKP sensor, etc. It seems to happen only at part throttle. Driving it ?hard? I don?t have much of a problem.

I assume this is ok. MAF shows around 9 grams/sec at idle which my Haynes manual says is ok. O2 sensors show they are switching rapidly from 100 to 850 mv.

The high fuel trims are at cruising. Letting off the accelerator and coasting they go down to single digits or zero.

I should be looking for.

voltmeter test with it last year. I think it checked for reference voltage and for ohms but don?t remember. Anyway they tested good. (According to Haynes manual).

appropriately according in terms of beign close to the guage on my truck. When the truck acted up over the weekend, I pulled over and unplugged the ECT sensor. It made no difference in the missing.

Multiple cylinder misfire code.

basically drilled a hole in the bottom of the cat, took a screwdriver to ?mash? all the insides of the cat and sucked it out with a shop vac. (Basically hollowed it out). Of course, I still have the code but my hope was to fix the problem if it was a blocked converter. I have never done anything with the converter on bank one.

Actually, a couple of times it would not start. Once it would start would barely idle but once warmed up it would act normal.

brake booster. Actually after fixing this is when it was hard to start.

me where to go from here and if there is a way with my scanner reading to rule out the map sensor?

dude, stop wasting our time. you won't follow the proper tech advice or diagnostics people give you, and you're a hack - only replacing one oxygen sensor and knocking out a cat. either take it to a pro and pay them to fix what you've screwed up or stop bleating.

ears have had a problem only in winter where it misses and backfires. The l onger I drive the better it gets. Over the last two years I have replaced p lugs, rotor, cap, coil, ignition module checked numberous times, lower and upper intake replaced, new fuel injectors, new fuel pump and filter, new CK P sensor, etc. It seems to happen only at part throttle. Driving it hard? I don?t have much of a problem.

temp so I assume this is ok. MAF shows around 9 grams/sec at idle which my Haynes manual says is ok. O2 sensors show they are switching rapidly from 1

k 2. The high fuel trims are at cruising. Letting off the accelerator and c oasting they go down to single digits or zero.

t range I should be looking for.

o a voltmeter test with it last year. I think it checked for reference volt age and for ohms but don?t remember. Anyway they tested good. (Acco rding to Haynes manual).

ng appropriately according in terms of beign close to the guage on my truck . When the truck acted up over the weekend, I pulled over and unplugged the ECT sensor. It made no difference in the missing.

t the Multiple cylinder misfire code.

asically drilled a hole in the bottom of the cat, took a screwdriver to mash? all the insides of the cat and sucked it out with a sho p vac. (Basically hollowed it out). Of course, I still have the code but my hope was to fix the problem if it was a blocked converter. I have never do ne anything with the converter on bank one.

r. Actually, a couple of times it would not start. Once it would start woul d barely idle but once warmed up it would act normal.

e power brake booster. Actually after fixing this is when it was hard to st art.

ne tell me where to go from here and if there is a way with my scanner read ing to rule out the map sensor?