97 Q45 barely running after minor repairs

[trailshredder]

Bought a 97 q45 that had codes for knock sensors, evap solenoid and needed a radiator and valve cover gaskets were leaking. Also did spark plugs, fuel filter and new plenum gaskets. Finished all these repairs and now when I start it, it revs up to about 2500 rpms, then drops to an extremely rough idle and eventually stalls. Runs smooth above 2500 rpms. When idling rough, it sounds like it is really sucking air. What could have I done wrong? Purred like a kitten before repairs, was just sluggish.

[carnal_c30]

Sounds like you may have a vacuum leak!
Check all your hoses, and you could spray carb cleaner while the engine is running around areas of potential leaks and you can probably find the leak pretty quick

[trailshredder]

threw a P0300 random misfire code tonight. would a vacuum leak cause a misfire? seems like a pretty broad error code.

[melvingoku]

i would think it would tell you what bank its missing on. I imagine if the leak was big enough it may.Just a thought but Ive herd you can only use certain plugs in these Q motor's. Maybe something to do with that? It sounds like a leak to me though. Id say go back over your plenuim and intake to make sure everything is hooked up forsure.

[Lokim]

99% chance you have a vacuum leak. When I started mine after doing the knock sensors, I had forgotten to connect the passenger-side PCV hose from the plenum to the VC. Sucked air super loud and wouldn't idle. I damn near had a heart attack! Grab a flashlight and inspect EVERY hose around the area worked on. You'll find it. Especially get your face down low and look under the plenum...

[trailshredder]

I used the NGK PFR5G11 (cha-ching). I`ll check over everything and post back what I find.

[trailshredder]

Couldn't find any loose vacuum hoses but I think I may have found an injector seal down in the valley that must have fallen out of the lower plenum. I would have thought my code would have been related to that cylinder though? do you think a missing seal would cause these issues? obviously not a good thing as there would be no compression in that cylinder. guess the throttle body and upper plenum is coming back off, hopefully can get the injectors up enough to get seal back in.

[trailshredder]

The fuel injector seal was the fix, runs great and idles great. Now for the power steering issue! I'll start a new thread for that. Thanks all for the advice.

[melvingoku]

good to hear!

[Q451990]

Was it a lower o-ring? If so, change your oil... your engine was getting way too much fuel and some of it was bound to end up in the oil pan.

Heath