Poor Accelleration when warm 9/29

[vortxrex]

Just replaced head gaskets on 91 Explorer. Runs fine for the first few minutes when cold, but as soon as it warms up it has VERY poor accelleration.

CEL is not lit. I ran codes & get RPM Idle out of range (code 13 & code 14) ON KOER.

At idle, the engine sounds fine, but the exhaust out the tail pipe sounds like it is missing.

I have cleaned the MAF & checked all my work, everything is plugged in & no vacuum leaks.

I am wondering if the Catalytic converter could have been damaged when I blew the head gasket ?

All suggestions appreciated

Dave Frank

 

[newbi]

Sounds like you'er on the right track. When I replaced my 94's cat with 80K it was in pieces. Your 91 is probably due for a new one either way. You can always get the exhaust system checked for excessive pressure before tearing into it and its fairly easy to do using the O2 sensor port for a pressure gauge. Should be pretty much unrestricted. Slight chance its the muffler restricting it also.

 

[vortxrex]

Turns out I had two cracked spark plug insulators, presumably from when I removed them from the heads when the heads were on the bench..... Sometimes its the basic things <grin> glad it is fixed

Dave Frank