I have a 94 4.3 liter S10 Blazer that experienced a havoc of EGR problems for about a year off and on.
Same sort of scenario with the problem with the engine light and EGR valvue after it was replaced at a shop as I had no idea what the hell was wrong. Five Hundred Dollars later and only knowing what faulty EGR valve symptoms were but not where it was I drove it home.
In my situation it took about 5days for the engine indicator light to kick on again which I ignored when I didnt have performance problems.
Day six on the way to work I noticed a considerable drag in accelleration and the same jumpiness I had when the EGR problem began the first time. As well as the Engine Lamp the ABS Brake light (both of the ABS lights) came on and I eventually coasted to a station called the wife and triple A*d its ass home.
I Busted out the Chiltons manual which had no picture of an EGR valve but gave replacement and cleaning instructions. Got online and found it was not an uncommon 1990s chevy engine problem and then on ebay for a picture of what I was looking for.
Using the Chiltons manual and the picture from Ebay I found it and cleaned out a pea sized chunk of carbon buildup that was blocking the float....used compressed air on all its chambers and checked all the valves and lines in and out cleaning out debris and put it back together. Ran great....
Then I used the other recommendations from the online info I recieved and changed out my fuel filter....airfilter....cleaned and regapped my plugs and from then on only used midgrade fuel or Supreme from Exxon, Cheveron or Shell which apparently has less crap in their gas. With all that I used fuel treatment every three months or so and maintained her myself. It took almost 1 and a half yrs to have to clean the EGR valve again....and I garuntee ya the mechanics said they replaced something that only needed cleaning...
POSSIBLE SOLUTIONS
Is there anything else its doing other than the check engine light being on?
Is it lacking Power in accelleration?
Die when idling?
Sound like a skipping fire order?
Did you replace the EGR yourself?
If not perhaps you should and check for carbon buildup...
Are you using a lowgrade Gasoline from AmPm or the other cheaper gas?
Have you checked other minor maintanance probs....
spark plugs/fuel filter/air?
When was your last oil change?
Chevy started making an engine oil quality detector that kicks in under certain engine stresses due to certain factors like viscosity,temp,etc.....and I believe that it kicks the engine light on when factors fit its prompt...
Does the ABS light come on too?
Mine does constantly now ever since the first EGR incident. I took it in for professional diagnostics and my AntiLockBrake System is fine and they dont understand why the sensor is freezing my indicator permanantly when I drive. It could be one of those situations.
Do you smell sulfur in the cab after quick shot of speed accelleration...ie pulling onto the freeway...passing someone...etc?
If this is so then you may still have an EGR problem. I noticed this sulfur smell a couple days prior to EGR float function becoming stuck open with pellet sized carbon build up and eventually rendering abnormal engine properties.
I know that its built with a self diagnostics blinking light system but it maybe a good idea to have an exterior shop diagnostics run several manual diagnostics in case its a computer or sensor error.
Thats about all I can think of...I admit its a little untechnical but I know what worked for me playing by ear in this experience.
I hope this helps in some way....
Good Luck
JAY D CLETUS
