The title says it all. I had the engine replaced with a good running 302. It came out of a 90 2 wheel drive. The truck is an 89 4x4 f-150. I get a check engine light after i drive it for a while. I can drive it but i want it to run better. Does anybody know if those years were even compatible? It ran good the first night heading back to my cabin. The check engine light came on that night too. Any help would be appreciated.

 

It sound like a vacuum leak to me.It would be easy to find out by checking injection code.Check for leaks at the vacuum reserve,egr valve.or the outlet on the intake.The engine should be the same.

 

I have heard of a semi-plugged catalytic converter messing with air flow. Plus when that happens the egr valve will go out. Since engine is new sounds like restriction in air flow.