I have a 91 STD that I recently replaced the lower spark-plug tube gaskets because I was getting oil on the spark plugs causing them to foul and subsequently...my car would stall and not restart.

I replaced the lower and upper seals along with the valve cover gasket. I replaced the spark plugs and plug wires and my cars starts but it sounds like its only running on 3 cylinders. I have no clue whats going on because my car ran fine today so I could park it in a safe spot to do the work. Can anyone steer me in some sort of direction?

I don't see how my timing could be off considering I never touched the dizzy.

The plugs are new, so they aren't fouled

The plug wires are new, so there's no oil in them causing it to misfire.

Any ideas? Possibly my dizzy decided to go out the very second I replaced something?

 

Just started it and pulled the plug wires one by one. The #4 cylinder is not firing. When I pull the plug wire there is no difference in how the car runs.

So, def running on 3 cylinders. Its going to be 9 degrees the next couple days so I will hold off until it warms a bit. I'm going to take off the valve cover and inspect the valve assembly on cyl #4.

All suggestions welcome still.

 

It wasn't misfiring prior to you replacing the gaskets right? Just clarifying before I start to research this.

 

It was not misfiring before I replaced the gaskets.

 

Did you make sure you have the correct firing order on the distributor to the spark plug wire?

See 2nd picture for reference.

http://www.autozone.com/autozone/rep...00c152800616af

 

Yea, its the correct firing order.

Ran a compression test...90psi in cyl #4. Looks like a bent valve. Not sure which one although I suspect its an intake valve. I ordered 2 new intakes and 2 new exhaust valves. I'm going to throw those in next week and do an MPFI conversion during that process.

 

even though they are new sometimes new plugs can be bad, put a old plug in and see if it fires. if it doesn't, try an old plug wire. sometimes where the wires are crimped it is also bad. do this one a time until you find out what's bad.

 

^ill give it a shot tomorrow. I hope I'm an idiot and it works. So much work I won't have to do!