Problem: Car barley idles, then shuts off, unless I continously give it gas. Backfires like crazy.

Attempted: Installed new Mass Air Meter

Just realized: Oil all over spark plugs/wires.

Could a bad valve cover gasket be the root of my problem? Or does the problem seem to go deeper than that?

 

Start with a new valve cover gasket. The oil on the plugs and wires will cause all kinds of issues to include degradation of the insulation. So long as you have it apart, it might be a good time to replace the plugs (cheap fix) and possibly the wires (depending upon how long they've been on the car).

Barry

 

This could be a number of things... the oil on the plugs may not be directly related to you root cause. Things to check.

1) Vacuum (may be a leak, but this test can also tell you if it's cam timing)
2) Cat (knock it with a rubber mallet and see if it rattles...)
3) Fuel Filter
4) Timing
5) Cam timing (gunna have to take the valve cover off to do it properly)
6) Compression

In that order. I've seen miatas with god awful compression on all 4 cylinders idle perfectly smooth... so that's really not likely.

Got any more details for us on how this started? Slowly/suddenly, after a boosted run @100 mph, etc. Any additional info you can give will help narrow down the search.

 

why did you install a new mass air meter? that might be your problem too.

 

I tried a new mass air meter/ sensor becuase I figured the old one might be shot-not the case. I ordered a new valve cover gasket, lets see if this remedies the problem.

 

vc gasket and plug wires.

 

yea, my valve cover gasket leaks too. When I get around 1" of oil in their, it starts missfiring. It's not enough to cause a check engine light, but it will run like hell till i fix it.