SES light comes on after reaching operating temp.

[joshua2903]

so recently my 95 GMC is running like crap, the truck has always been maintained it has 215,000 +or- I firsst noticed some slugishness while driving so I had the fuel system flushed(turns out this is NOT recomended by GMC and is a BAD IDEA) the flushing actually made things worse, the tech actually changed my fuel filter before flushing so I assume he flushed everything into the new filter, I took the truck home and replaced the fuel filter,EGR valve,idle conotrol actuator and the purge valve actuator. now the truck will idle fine if its facing downhill until the truck reaches the operating temp then the service engine soon light illuminates(code 32) if the truck is facing uphill the truck will idle very rough, what could cause this? could it be the fuel pump? or maybe the cheap-O- parts from autozone? the uphill vs. downhill makes me suspect the fuel pump is weak, any ideas?

 

[Molson02536]

so recently my 95 GMC is running like crap, the truck has always been maintained it has 215,000 +or- I firsst noticed some slugishness while driving so I had the fuel system flushed(turns out this is NOT recomended by GMC and is a BAD IDEA) the flushing actually made things worse, the tech actually changed my fuel filter before flushing so I assume he flushed everything into the new filter, I took the truck home and replaced the fuel filter,EGR valve,idle conotrol actuator and the purge valve actuator. now the truck will idle fine if its facing downhill until the truck reaches the operating temp then the service engine soon light illuminates(code 32) if the truck is facing uphill the truck will idle very rough, what could cause this? could it be the fuel pump? or maybe the cheap-O- parts from autozone? the uphill vs. downhill makes me suspect the fuel pump is weak, any ideas?

Check to make sure you have replaced the egr valve with the right one. There are 2 types, one is a vacuum type and the other is a pressure type. Also inspect the egr soleniod and wire leads to make sure its operating properly.

Also check your vacuum lines for any damages such as cracks or the lines being to soft. You should have 2 lines as I recall, one line to the egr valve, then to the sensor and then from the sensor to the front of the throttle body.

Start with that and keep us posted.

Molson02536

 

[joshua2903]

I will tackle this monday, yesterday I finally got the truck driveable but soon after I discovered water leaking from the back side of the waterpump, i hope its just the pump gasket but it is hard to tell, especially in the dark. is there any chance it could be the block? it only leaks while the engine is running and like i said it was already dark by the time i noticed, the truck has only been over temp once and just breifly,like maybe a sticky t-stat,I figuered i would need to be replacing a waterpump soon but the truck has been parked for over a year(i start it every other day and drive it around the block to get the lubricants flowing) thanks for responding i'll try to keep you posted and take some video of the repairs to post. thanks.

 

[joshua2903]

oh shoot, I forgot to tell you how I got the truck running again, the MIL was illuminated and the codes i now get are 35(IAC error) and 44(o2 sensor, (lean mixture?)) I had replaced the IAC valve and I never set the idle, the truck was acting like it was starving for fuel, sputtering at acceleration and dying unless i feathered the accelerator, once i adjusted the idle the MIL de-energized but my truck is idling at about 1100-1200 RPM, this seems high but it does drop down to 700-800 RPM when placed in drive,I am going to order AC delco replacement parts(IAC,EGR,MAP sensor,ect...) the parts I picked up at autozone have me feeling kind of sketchy, the EGR valve was like $20 but an AC delco part is more like $80(online).I used to be able to buy American made parts but recently I noticed everthing at the local parts store is made in tiawan or mexico(I avoid chinese at all costs, just a personal pref. not trying to offend anyone) anyway thanks for your response, i'll check to make sure I got the right EGR,and get the waterpump replaced(fingers crossed).