Was this a cylinder compression test or a catalytic converter pressure test?

 

With the plenum would it constantly misfire or just at times (as in my case)?

 

Depends on what mood the engine is in at the time....... not precisely consistent.

 

Yeah its completely random. It's been running perfect for about a week and for about 45 minutes today and all of a sudden its blasting fireball out of the muffler!

 

Could be a failing sensor.... Crank Position, Cam Position, O2...... Trouble with that is, I have no idea how to test. You would need to be able to do some data logging, and then compare various sensor inputs between when it was running good, and when it wasn't.

Get any spark knock? Excessive oil consumption? Fouled plugs?

 

CKP (Camshaft) sensor could be cracked or an issue with the pigtail. That'll cause misfires.

 

Yup it burns oil, especially lately. It also uses coolant at times.

 

I should also mention it makes a hissing sound when it starts to run funny if it is just idling. Sound come from the passenger side of the engine.

 

Take another look at the plenum.

 

Some new developements! I just got off the phone with a friend who insists it's the timing. He is saying the plenum would set off a vacuum sensor and show a code.