'92 Q45 Not Running Right

[Lou92Q]

My '92 Q45 has an intermittent problem. Sometimes it runs fine. Then at startup or sometimes after it's been running OK for a while, it starts acting like it's running on 2 or 3 cylinders and I get thick black smoke from the exhaust. Sometimes white smoke. RPMs will go down to 200-300 then it shuts off. Sometimes it starts right back up fine, sometimes it starts up but does the same "skip" thing. It did this once before and it ended up being the MAF. I've cleaned the relatively new MAF (it was replaced about 3 or 4 years ago) and I also tried throttle body/air intake cleaner.

About 4-5 years ago I removed the plenum, replaced all of the fuel injectors, the knock sensors, spark plugs, a couple of bad ignition coils and all of the hoses associated with the intake/plenum. It's run great since then until now. My mechanic says it's not throwing any codes.

I'm thinking about replacing the MAF again just to see if that fixes it.

Any other ideas would be appreciated.

[elwesso]

When you replaced the MAF, did you replace it with new or a used one? Sounds like a MAF related issue. Have you replaced the fuel pump or checked for fuel pressure? Sometimes a bad fuel pump can cause similar issues to a MAF.

[Q451990]

Yeah, sounds MAF related to me too. If you tap on the "black box" of the MAF when it's acting up, does the idle behavior change?

[94Q45Beast]

Yeah, sounds MAF related to me too. If you tap on the "black box" of the MAF when it's acting up, does the idle behavior change?

If so then most likely the male side of the MAF connection pins needs to be re-soldered from the inside.

[Lou92Q]

Thanks to all for input. I did replace the MAF with a new one 3 or 4 years ago. I will try tapping on the MAF and also check fuel pressure. Fuel pump has been replaced but it's been several years so that's a definite possibility.

[Q451990]

You can also try wiggling wires to and around the plug to the MAF, those sometimes go bad.

[94Q45Beast]

If the connector is bad you can always solder the wires to the MAF like I have.

[TriniQ45]

Hey Guys,

Where can i find replacement intake hoses for under the plenum of my 94 Q45.?

Peace.....