1989 Help

[Tx Firefighter]

Concerning your check engine light issue....

Replacing the EGR valve might or might not solve your trouble code. The intake manifold often gets clogged with carbon which is the root of the check engine light. The EGR valve functions perfectly, but with clogged passages, you're gonna get a code. The way to check it is to start engine and let it idle. Now, grab the EGR valve and open it with your fingers. The engine should stumble significantly. If not, you've got clogged intake manifold passages.

Concerning the power issue......

I'll quote your first post in this thread. "The engine revs high and does not deliver on the power then suddenly after a few seconds the power is all there wondering what is the problem"

You've got a transmission or drivetrain issue, not an engine issue. Sounds like trans slipping if its an auto or clutch slipping if its a standard.