You must have missed a clog. Without the egr on you should hear a major vacuum leak and an exhaust leak. Which ever one you missed you wont hear. I dont remember off hand where the ports go but the vacuuum one has to go to a place in the intake where it feeds all cylinders. So if its a TBI it will go right near/under the TB. I think the exhaust side goes to the center "crossover" in the intake where it lets exhaust go from one head to the other, dont remeber for sure. When you say "holding the EGR open" you mean with your fingers, not a vacuum pump right? If you open it by hand at idle you should get the engine to stumble for sure. GL
Hi folks here goes.
> 1990 c1500 350.
>
> Sets an egr code for quite a while now. Doesn't seem to store it but it
> the light will come back on after high speed cruising. Couldn't get the
> engine to sputter when I held the egr open at idle so I was told the port
> was clogged.BTW the egr seems to work fine when I rev the engine as I can
> feel it going up and down so I ruled out the switch.I removed egr and intake
> manifold and cleaned out both with carb cleaner and manually chipping away
> carbon and using compressed air as well.. Reassembled and the truck runs a
> lot better with no pinging on acceleration but the darn code came back and I
> cant get the engine to sputter at idle by manully holding the egr open. Did
> I miss a clog in the intake somewhere??. When I started it without the egr
> in place the engine run like crap for a few seconds till' the ecm took over
> so the ehgine must be breathing through the egr port ...right??. What are
> the socket head plug screws on the underside of the intake for??. Was I to
> remove them as part of the cleaning procedure?? Could the egr valve itself
> be faulty as in possibly too stiff or an internal vaccum leak??
>
> Sorry for the long winded post, can anyone help please?
> Paul. >
>