my 1990 88 3.8 does not run strong unless i disconnect the egr. it has lack of power and bad mpg. I HAVE REPLACED THE EGR AND I HAVE THE SAME PROBLEM. WHEN I DISCONNECT THE EGR IT RUNS PERFECT. COULD I HAVE PURCHASED A DEFECTED EGR OR COULD IT BE SOMETHING THAT IS NOT MAKING THE EGR WORK. THANKS SX455

 

There is a tool that you might be able to rent at an auto parts store that checks EGR valves. All it does is pulls vacuum on the valve and you check for movement. It also makes sure your EGR gasket surface seals well.

If your EGR is giving you problems the first thing I would do is make sure your car doesn't have any codes. Those are a good starting point for troubleshooting, that is why they put the ECMs in cars. If it doesn't have any codes then it makes things tougher.

How many miles does your car have on it? Have you noticed any blowby from the rings during heavy acceleration? The reason I ask is because I had a 91 Buick LeSabre station wagon that had poor driveability because the engine was worn so much that the EGR and PCV were pumping so much junk into the cylinders that it caused a miss. This might be similar to the problem you are having. Just a thought.

 

THANKS FOR THE INFO. THE CAR HAS 65000 MI, THERE IS NO BLOWBY. DO I NEED A TECH 2 SCANNER ? WHO WOULD HAVE ONE? MY MECHANIC DOES NOT HAVE ONE

 

You don't need a scan tool to get codes from and early 90s GM. All you need is a paper clip. Short the A and B terminal together of the scan tool connector and then count the flashes. It will flash 1 - 2 three times and then go into your codes. After it is done flashing each code three times it will flash 1 - 2 an additional three times before starting over. Get the codes from a Chilton's guide or go to the parts store. They will usually tell you what they mean.

 

check the egr port for build up. alot of times the intake will build up junk and get plugged just as if you had a bad egr