Completed the PCV system replacement and ended up with a misfire on #1 cylinder (P301 code). Went ahead and replaced the sparkplugs, wires distributor cap and rotor to no avail. Removed and cleaned the #1 injector- no improvement- so went ahead and put in a new injector. Still have the same problem. The MAF and all associated vacuum hoses were replaced last fall and it ran well up until this shot at maintenance. I also checked the compression and found all cylinders to be between 170 and 180. I'm stumped, any suggestions as to what to check next?

 

Really sounds like you did everything you could do. If I think of anything else, I'll post.

Did you get all of the manifold bolts tight?

 

I'll check the manifold bolts again tomorrow. I did struggle a little bit getting it all back together, especially the bolt underneath the manifold. If I pull the wire on # 1 there is no change in the engine idle, whereas any other wire pulled (with 1 reconnected) definitely affects the idle.

 

Did the problem start when you did the PCV job? Did you ck for a large vacuum leak near #1 intake (like something got stuck under the gasket or tore the gasket maybe)?


Does it run on 5 cyls when revved above idle?

 

This issue appeared after performing the wonderful PCV replacement. I checked all the manifold bolts and they're tight, so that wasn't the problem. I really had a struggle getting the lower (the one accessed from under the car) manifold bolt lined up. This led to quite a bit of manipulation of the manifold to finally get the bolt in. May very well have screwed up the gasket at that time. I guess I'll break down and pull the intake back off and inspect.


It appears that cylinder 1 is not kicking in above idle.

 

 

If #1 is not running above idle too, then doubt it's a vacuum leak (unless it's massive!).


You might want to ck your compression again; esp on #1.


Did you ck spark on #1?


If you had plug wires swapped you would have at least two cyls not running; not one.

 

Mystery solved. Pulled the intake manifold off and the gasket was torn around the number 1 hole. Picked up a new gasket from the dealer that actually had metal backing (unlike the first one that came in the PCV kit). Put it all back together and it's running perfectly. Really not fond of that bolt on the bottom of the manifold.

 

Glad you are back on the road.