so i cleaned the egr valve with nothing but a wire brush, got a lot of carbon out of it. reinstalled witha new gasket, i also put in new acdelco plugs with a .35 gap. now it feels like i have a very severe miss, or like it wants to stall, whether parked, driving or stopped in gear. ive gapped and changed plugs dozens of times so im assuming the egr is actually bad and cleaning it made it worse, maybe, yes, no, any ideas would be really cool. thanx

 

Hmm.. Weird.. My references show 0.045" gap for the 4.3L TBI and CPI in '92.

It is very possible that the EGR is bad as well... When you apply a vacuum to the pancake valve, does it shrink up? Does the pintle move freely?

 

With the engine idling, try tapping on the top of the EGR valve and see if the idle changes. It may be that a piece of carbon is not allowing the pintle to fully seat at idle.
When you had the EGR off, did you manually operate the valve to check for smooth operation?

 

kyle how do i apply a vacuum to the valve, do i open the throttle? and its the 2.8 that has a gapping of .45, and i also operated the valve manually and it felt very smooth with a slow release. i would try and clean the passage on the t.b. but its on the back and i had to remove the coil just to get to the bolts, can i use seafoam on the egr, chilton says its not a good idea to use any solvents.

 

Use the gap as listed on your emissions sticker if its still there, but both of my references list a 0.045" gap for both of the 4.3L engines offered in '92 (tbi & cpi).

You can use seafoam on the EGR valve, just make sure that you don't get any of it near the rubber diaphram on the pancake valve side of the EGR.

As far as applying a vacuum, I have a little hand pump that I use for vacuum bleeding brakes that I would use, but...

 

ya know i got chiltons saying .45 now while haynes says.35, maybe i got the gap alittle to small? the thing is ive always ran at a .35 gap maybe .38 but always around there. what are u looking at?

 

AllData & GM ESi.

 

You can prolly throw out the HAYNES manual, they are crap. Try HELM manuals if you want a real good set of manuals.

 

my emissions sticker says .35 so i guess haynes was right.as far as the egr, i try tapping the valve and no movement of the pistle. i figured what the hell i can get an oem match for 50 bucks just down the street, so why not. i get the thing in there only problem was i could not rotate the valve diaphragmassemblyto match up with the vacuum hose. i ended up splicing a piece of hose that i cut off my cruise control( i had slack) and ran around the egr and into the vacuum line. all that and i still have the problem.
im now leaning towards the plugs, the gap is right and the wires are on tight. i applied anti sieze, maybe some/ or some oil got on the electrodes. should i maybe put some of that eletrical grease inside the boots.
also i was wondering if my fuel press regulator was going. would this give symptoms of a missfire. and how would i go about checking the pressure on a 92 tbi. i dont see any sort of schrader valve?

 

I tried to see if there was a TSB that would explain the discrepency in the gap size, but couldn't find one. Info going back that far is sketchy at best with most sources.

You could pull the plugs and check for signs of a cylinder miss fire, but if it only does it randomly, chances of you finding anything are slim to none...

As far as checking the fuel pressure, I'm pretty sure you have to get an inline 'T' that will have a shrader valve on it to hook up to a conventional fuel pressure tester.