part throttle 'lugging'/missing

Page 2 of 2  
. . . concerning engine lugging and multiple sensor replacement, and the value of being able to read spark plug condition.......
(for those who care....read the thread for all
the impotent stuff...too much cut and paste)
2 cents worth......
#1 Original plugs had light brownish coloring.... (a good indicator of additives, was the electrode burn't?~lean condition~)
Screams out Fuel Additives have been used, and likely wrong fuel mixture.
#2 Catalytic Convertors getting hot and possibly glowing red.....no black smoke out the pipes...
Screams out Lean Burn condition. (vacume leaks??)
#3 O2 sensor reading rich condition..... (coupled with the above indicators...)
Screams out ECM possibly dumping fuel to correct a misfire detection or compensate for a lean condition.
#4 Multiple codes set.......and sensors changed to correct the problems.....
Screams out....the need for the truck to be put on an oscillescope and have an end put to all the guess work... (multiple codes and sensor failures are extremely unusual)
#5 (what started the thread) Engine lugs on part throttle, engine surges up and down like it's trying die out....surging, seems to have good power under full throttle...
Screams out fuel mixture..OR...ignition trouble.. (weak spark at the plugs)
..... cheap suggestion
before you go spending more money..... hit all the vacume areas and around the intake with some starting fluid and see if you can locate some vac leaks........the engine rpm should increase noticeably on a lean running engine.......and decrease noticeably on a rich running engine.
If you "suspect" the EGR diaphram is sucking air.....stick a long enough vac hose on it, and suck it down with yer mout....see if it's holding vacume...no need to buy a vac pump when yer lungs will do the same thing.
take a look under the hood at night....no lights around.....see if there's any fireworks going on up and down the wires and around the primary ignition system from shorting.
...... remember......if it's running fairly good at cruise, during full throttle, or if it runs good only some of the time....it's still capable of running good...
which means....
The ECM and THE SENSORS are capable of maintaining the fuel ratio and spark...enough to let the engine run well (which means they're likely working good), The catalyst is not likely restricted enough to cause a loss of power (you would be feeling a power loss all the time), And....... the overall condition of the engine is within specs, allowing the thing to be CAPABLE OF RUNNING GOOD even some of the time. (compression, exhaust flow, timing, fuel flow)
............which would lead me to believe you've got a simple problem with a simple fix,
and what's simpler than bad ignition components, vacume leaks, and dirty throttle body.....all of which you can fix yerself.
jest my 2 cents worth, marshmonster ~:~
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
yeah, i will definitely note this for future reference. I did not consider that the intake was leaking... i just had it fixed within the last year...twice
It was leaking in the front previously... and i was able to notice oil and coolant , but seemed to run good...unlike this time around, w/ the rough running. Apparently, it is leaking from the rear. the shop had sensors in the tailpipe as they sprayed whatever it is they spray around intake manifolds. jim

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim, you must be a mechanic by trade as that is exactly what they told me- 3 hours labor 0 bucks or so

<can't
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

byproducts
few
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
well, it did not fix my problem, and they want to check my 'computer' out. The owner of the shop said the EGR was functioning, and basically it is either 'off' or 'on'. His worker, said it was leaking vacuum....

that
hell
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.