I am still trying to track down a lean fuel condition and I have checked and/or replaced almost everything. Again the vehicle is a 95 Jimmy W series Vortec 4x4 (OBD2 switchover year).
When I scan the data stream, I get a +25% on long term fuel trim. Here¹s what I¹ve done to eliminate the problem:
- replaced the fuel pressure regulator and nut kit on the CPI unit
- plugs/wires/cap/rotor
- replaced all old looking vac hoses and tested them for leaks after (all good)
- new fuel pump and filter
- egr, IAT, MAP clean and gasket replace (TPS adjusted checked ok)
- O2 sensor replaced and tested
The only other thing I can think of is that the clmate control switch has a leak (read:hiss) in it and needs to be replaced. Would a leak at this switch cause the lean fuel condition? I had a bad coil before also so I may try replacing that also (I have one kicking around already so why not..)
There is a slight hesitation off the line but it¹s bareley noticable. Every once in awhile I get a random misfire code also. With all the lights off in the shop, I cannot see any arcing of the wires, cap, etc. Does this sound like it could also be the ignition module? As far as I know it times the spark/advance??
Thanks again! I appeciate all your help here guys! Andrew.