black smoke, random shutters thruout rpm range after oil change

[NPostman]

i normally have the stealership or jiffy lube change my oil. this is the second time ive changed my oil myself. i have a 94 q. i took out the maf last time and apparently damaged the pins on the inside of it somehow so i replaced that. i tested this new one and its all good. theres a small amount of smoke coming out the back constantly that seems to increase with rpms consistently. all the cylinders seem to be firing correctly because it runs pretty smooth. last time one of the spark pugs wires came off somehow and that caused the cylinder not to fire which caused the smoke and really rough idling so im pretty sure thats not it cuz it idles and stays smooth thruought acceleration besides very infrequent bucking. it also kinda surges slightly while idling and pushing the brake harder kinda makes it go away. maybe thats a seperate problem. anyways, any help would be useful

[elwesso]

Welcome to NICO! sorry i missed your post.

From what I understand you replaced with cheap sparkplugs, so get that taken care of so we can eliminate that. Rememberthe Q has no spark plug wires.

[NPostman]

yes i did and the problem still persists. i figured cheapos would at least show if it was worth investing in better plugs. it ran fine tho before i changed the oil. thats the confusing part. all connections are good, all hoses are unblocked and in good condition and attached correctly. ive heard that it could be tps or maf but i want other opinions before i spend the time and money on it.

[maxnix]

i figured cheapos would at least show if it was worth investing in better plugs.

How would that work?

Try a search on Bosch sparkplugs.

[NPostman]

the plugs in there worked before the oil change, but afterwards, because of whatever the problem causing the system to run rich, were blackened so i replaced them with the same kind of plugs with the same gap that worked fine before. thats how it works. with my logic. Anyone in cali wanna sell me a maf? i need it really soon.

[maxnix]

the plugs in there worked before the oil change, but afterwards, because of whatever the problem causing the system to run rich, were blackened so i replaced them with the same kind of plugs with the same gap that worked fine before. thats how it works. with my logic.

With respect, I do not think that is a cogent argument for not using OEM specified plugs.

I mean, if you lived on Big Macs all your life and you were suddenly informed your cholesterol count was 900, would your "logic" compel you to keep eating Big Macs because you weren't dead yet?

[NPostman]

good point. i have to admit. well i got a maf coming cuz im pretty sure thats my problem, and i will soon be getting oem plugs. i'll let you know how that goes.

[goody90q45]

Check the connector also. The female pins have a tendency to open up and not fit tight on the male pins. Probably from being wiggled too much or from being removed to access the oil filter. Take a very small screwdriver and compress the female pins and you'll feel the connector fit snugly over the male pins.

The guy I sold my 90Q to called me yesterday with your same symptoms and this was the only problem. Fixed in 10 minutes. Good luck.