I have just purchased this vehicle for my daughter so I do not know about status of LIM and UIM gaskets......while I'm replacing plenum I plan to go ahead and put in the metal gaskets while I'm at it...... THEN, it dawned on me while out today that in an effort to get this engine running again, I sprayed Starter Fluid into the intake to see if it'd just run a second or two.... THEN when I put another module on it today....I guess with the correct spark, it ignited the fluid I spayed in the intake that was sitting in there....... my bad...... lesson learned.

I replaced plenum, and switched out ignition module...... engine fired right up....but it appears it has picked up a valve tap....... wasn't doing this before the backfire...... help?

quite possible something in the valve train could have bent or stud pull out or just backed off the retainer on the rocker if you are lucky, have to take the covers off and look

I just put the covers back on after gasket replace, and replaced plenum and plenum gaskets..... car was running last night, went to parts store and when I got back 30 minutes later engine would not start.... it would 'cough...cough...cough...cough' for about 10-15 seconds then complete die.

Well I replaced the plenum, and it ran well for about 20 minutes, then died, would not start..... the plugs looked nasty so I replaced them...... ran great...... for about 30 minutes then slowly died....would not start again (here we go again)...... now it won't start again...... this thing is a mystery. (Bad Head Gasket??)

if it had a bad head gasket, you can check the compression and the plugs there should be some sign there. i think its the CKP or its wiring.

The 3 times now this has happened, I never get it started again, until I replace the plugs or the module....then it starts, runs for about 25 minutes dies again, until I do something else. We are going to throw another CKP on it just to see....... Will update.

UPDATE: I pulled my new plugs and the ends were all wet with antifreeze..... think I've got blown HG...... I got some work to do.