1988 Oldsmobile 98 Error Code 64 PCM PROM Failure

I have a 1988 Oldsmobile 98. I have recently fixed a bad PCV Valve that giving a Error Code 44. Now that is fixed, car is running very good and after about 100 miles the Service Engine Light comes on and gives Error Code 64. It does go off after a while but comes back again after a while. Where should I start with this problem???

64 is EGR valve flow code. Pull the EGR and inspect it and the port for carbon blockage, if its there, clean it out. The valve may need replacing also, even if you can't see a problem with it.

Thanks for the info. Thats interesting with the problems I have had with that part. I already replaced the EGR about 3 weeks ago, the new one was making a humming noise and I found that the parts store sold me the wrong gasket and it was causing air to get into the valve. I got the correct gasket and the car started running great. With car running with the wrong gasket, could that cause the egr to go bad?

No.

Nope, that doesn't work. Cleaned the new egr valve again but code still comes back. Drove it about 140 miles without air conditioning and light did not come on. When ran air conditioning for about 50 miles afterwords the light came on. Seems to come on and off more when running A/C.