1995 GMC Sonoma

1995 GMC Sonoma, 4.3L TBI 2-wheel drive Automatic. Will not go more than 20 MPH, will stall out and die if you try pushing on the accelerator. Had a code of 32 saying the EGR Valve. I bought and put on a new EGR Valve. Still does the same thing–no power and only 20 MPH. I’m wondering if it could be that the catalytic converter is plugged or maybe a bad fuel pump. Need advise, thanks.

I would first check for an exhaust restriction, ie plugged catalytic converter. Here’s how.



Are you sure your truck has TBI

I thought a 1995 Sonoma 4.3 uses an early “spider-type” fuel injection setup

Do you have a plastic upper intake . . . if so, you do not have TBI

Once you determine what setup you have, please measure fuel pressure

It would also be a good idea to measure exhaust backpressure. That’s not a big deal and would quickly determine if your cat’s good or plugged

By the way, is your truck OBD2 compliant? The underhood emissions label will tell you. Do you have a 16-pin data link connector under the left side of the dash?

You could TEMPORARILY unbolt the cat and drive the truck. If you’ve got normal acceleration, you’ve found your answer

If the cat is plugged, you might want to consider the possible reasons . . .

Excessive oil consumption
engine overheated
ignition misfires

They do wear out, and maybe it’s just time

Another idea. If something is holding the EGR open all the time, this could possibly happen. And replacing the EGR wouldn’t fix it. An EGR does its thing in response to a command from another part of the engine. That command might be the problem. If the EGR was open all the time, you’d notice it at idle too, you’d have a very rough idle, maybe stalling at idle at stop lights. If you are still getting that EGR diagnostic code, even after replacing the EGR, ask you shop to look into what controls the EGR. Usually there’s gadgets involved with all this, EGR modulators, etc.