New to forum, got some problems with 95 maxima

[zachs_maxima]

I've got a 95 maxima, auto (think it's a GLE, has bose audio)...170k miles, replaced all the bushing with ES poly, new struts, all around, new brakes.

The idle is very high, around 1500rpm or so. I'd be more specific but the tach is going crazy too.

The CEL is on and gives me a code 25. (idle air control)

I took the IACV off last night, disassembled it and cleaned it, no change. The idle is still high...unless I disconnect the feed tube from the airbox. If I do that, it kills the engine, if I put my thumb over it, it draws a hard vacuum and the idle drops to about 500rpm.

The other thing it will do, when in gear, is occasionally drop a cylinder, or suddenly jerk. It feels like the car just shuts off for a fraction of a second and then comes back on. That one's a mystery and has never generated a code.

So my three problems:

1) IACV / IAC system is throwing codes before and after cleaning.

2) Tach is going nuts. (surges to 5k, suddenly drops to 1500, hangs at 3000, goes all over the place, totally random)

3) Occasionally drops a cylinder or feels like it does, only at idle in gear, never under load.

Any suggestions?

-Zach

[MaximA32]

Sounds like a vacuum leak. Have you checked all the lines and such?

[zachs_maxima]

That's what I thought at first too. I sprayed non-chlor brake cleaner, and then berryman carb cleaner all over the place and there was no change in rpm.

This afternoon, after I posted this, I sprayed carb cleaner through the airbox (or whatever that block is after the MAF that connects to the IACV via the 1" hose and to the TB). This seemed to help oddly enough. Now it purrs fairly smoothly at about 800rpm in Park, about 650 in Drive. The tach is still off...most of the time, and since I cleaned out the item I've decided to call the airbox, it hasn't dropped a cylinder. What the hell is in that thing anyway?

[MaximA32]

Sounds like the MAF was dirty. Better hope you didn't ruin it by spraying carb cleaner on it. Not to be an alarmist but that wasn't a good thing to do.

[zachs_maxima]

No worries, didn't spray carb cleaner on the MAF, I have MAF cleaner for that.

I cleaned out the "box" between the MAF and the TB, whatever that is and...strangely enough, that seems to have helped.

[mr0x]

I think bad MAF or lots of air is getting in there through a leak.
Does the 95 have OBDII live data? It would be really useful in this case.

[zachs_maxima]

I don't think so, no code readers fit it.

The IACV problem is back again. It seems the unit is non-functional. If I disconnect it, there is no change, the idle remains high. I tried cleaning it again, no change.

If I tap on it while the engine is running, the idle will fluctuate, but that's about it, and only by about 100rpm.

I think a new IACV is in my future.