[ikaria73]

Ok, so I can't seem to get around code P0303 and P0455. Over the past few weeks I have replaced the plugs, ignition coils, fuel injectors and purge valve with no luck. I now am assuming it's either an air intake issue or a short. The only time this will occur is when I am at a stop light and the engine starts to idle down...after about 5 seconds the misfire will occur. This does not happen when I am on the highway which is why I'm leaning toward an air issue. I have not replaced the MAP sensor but might do that next just for the heck of it. Am I missing something? Any one else have a similar misfiring condition that they can't seem to get rid of?

 

[electbc]

Only a 303 misfire? hmm When my throttle body acted up, it was a P0300, random misfire. How is your throttle body? Nice and clean? if not, a good cleaning would be beneficial.
New plugs, coils and injectors should have cured a specific cylinder misfire. Maybe a pinched wire to injector or coil pack? The P0455, well that is probably something different. Try posting on Acadia Forum, there are some wiz mechanics there who may be able to walk you through it.

 

[ikaria73]

I've cleaned the throttle body with cleaner and I could try giving it another go. I found some info on the EVAP Vent Solenoid Valve and how it operates compared to the EVAP Purge Valve which I previously replaced and plan on check that solenoid value to fix the 455 code. I'm hoping it some how is tied to the engine misfire at low ideal...probably not.

 

[SR]

Faulty gas cap on the 0455?

 

[ikaria73]

Oops, yeah I changed the gas cap too.

 

[electbc]

Do you or did you have a milkshake in the air intake?

 

[ikaria73]

Ok, so I think I figured it out. I recall seeing oil on my spark plugs and I now believe I have a spark tube leak issue. I have no desire to replace the cylinder head but I did see on the Acadia forum where some one applied a vacuum to the tubes and pulled in a sealant. Has anyone tried that? It sounds easy enough just need to get a vacuum along with a vacuum attachment to fix to the top of the tube.

 

[ikaria73]

Well, the vacuum didn't work for me. Still stuck with a p0303 (not worrying about the P0455 for now). Was thinking of trying a "hotter" plug and maybe even heavier weight oil but I'm not too optimistic. I'm also going to run a compression test.