89 240sx Coupe Idle Problem NEED HELP Please!!!!

[_S13_]

last night the idle started to jump up and down going down as far as 400rpm all the way to 2000 rpms....

Then the idle just stayed down towards 400 and 500 rpms and runs like ****....So i figured i would just park it and hope that it wouldnt do it in the morning but i was wrong it did it all day but now its dieing when i come to a stop....So i pulled into a parking lot and smelled the exhaust and it smells like stright gas comeing out of the muffler....

Me and my father checked for a vac. leak but there wasnt one...

I know ill get the usual "SEARCH IT" reply but i have and there is nothing that relates to what is going on with my car....I really need help on this one because it is my only way of transportation..

All the help is appreciated....

Thank you Adam

[Silvia007]

The only problem with this scenario is that there could be so many possibilities such as bad ground, vac leak, bad mafs, tps, leak in intake after mafs, plugs, etc. etc.

Things that will help is what has been tried, does it get regular tune ups, and so fourth.

I'd say that if it's been a while since you cleaned the mafs, run to your local auto parts store and pickup some electrical contact cleaner and spray the element in your mafs.

[_S13_]

Yes it gets regular tune ups... I mean it couldnt bee too much it only has 80k miles on it...so Idk

[sr20deTsomeday118]

ok my 91 240sx coupe just started doing the same thing...i just replaced my valve cover gasket and it started happening. im thinking bad o2 sensor but thats because one of my friends had the same prob on his saturn with the rpms jumping like that...ima take my to the local autozone to get checked. the diagnostic is free there so i suggest that. i really hope its that easy