Poor Accelleration when warm OK COLD ?

[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 12 & code 13) ON KOER. all other codes normal & Base timing correct

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 & is somehow restricting as it warms up ? Head gasket symptoms were pressurizing the coolant. some steam out the exhaust, but not the typical plumes of white. No coolant in the oil (changed it anyway)

I had the heads checked & surfaced (there were no cracks). I used the Victor gaskets (it had the felpro when I took it apart)

Now its all back together & running poorly when warm, but fine cold.

All suggestions appreciated

Dave Frank

 

[vortxrex]

Problem Fixed !!

Turns out I had a cracked insulator on the No. 6 Spark plug. I went ahead & pulled all six plugs & found a small crack on another of the insulators as well.

My guess is that I cracked them when I removed them from the Cylinder heads (Heads were on the bench) Spark plug socket did not have the foam protector & I removed them by smacking the rachet handle with the palm of my hand not realizing that I had damaged the plugs.....

This also explains the KOER Codes 12 & 13 which indicate RPM out of range & the crack opened up w/temp causing different warm/cold symptoms.

Yes I am very pleased to have my X running great again !

Dave Frank