Stuttering\Stalling?

[nchopp]

Talked to Wes already a bit, but figured I'd throw this out here in case someone else thinks differently.

A few weeks ago I was driving back from Madison to visit the parents and the Q started stuttering pretty badly after passing someone. I pulled over to a side-road and it died almost right away. I popped the hood, everything looked\smelled\felt ok, not overly hot, etc. I let it sit for about 10 minutes, then tried starting it up. Started smoothly on the first try, got back out on the highway and it started stuttering again. Tried changing just about everything up - slow acceleration to moderate, A\C on or off, shifting, all that. Kept doing it. I stopped at a gas station and dumped in some fuel injector cleaners, figuring maybe it's that crappy Wisconsin gas (ethanol, blech), but no luck. It's been a few weeks and several tanks of gas, and it's still happening. Some days it'll be fine, other's it's just being a pain in the arse. It stalls maybe 2 or 3 times out of 10 stops, then (usually) starts back up again. It seems to get worse when it's hot.

Wes suggested MAF. Any other thoughts?
Modified by nchopp at 10:30 AM 7/18/2005

[maxnix]

Don't know year, mileage, nor service history, so it's a crap shoot for us.

Check the MAF, try Iso-HEET, and BG44K before your next oil change.

How new is the fuel filter? Fuel pump? All else up to snuff?

[96Qowner]

I'd be really surprised if it isn't your MAF. It sounds like a particularly bad case, but the symptoms match well enough.

A good cleaning will tell you for sure. I lived with a failing MAF for over a year - cleaned it a half dozen times. Try that first.

http://www.q45.org/maf.html

[nchopp]

Oops, sorry. 1993 Q45, 193,000 miles, oil change about 2,000 miles ago, all regular maintenance was performed by the previous owner.

[3Q Jay]

me thinks fpcu. won't keep up with fuel demand if damaged.

[nchopp]

FPCU? This is... what, exactly? Sounds more expensive than an air controller. :-\

[Rex]

FPCU? This is... what, exactly? Sounds more expensive than an air controller. :-\

Fuel Pump Control Unit.

Does your fuel pump humm? (sound like bees in the back seat)

[Th4rg0r]

Pump wouldn't hum if it's changed without changing the FPCU ... I think.Check it by using the grounding alligator clip trick. If it runs fine using the clip, well, there's your problem right there.

Air filter changed/clogged? I think Wes's right though. Stutter on idle? Over 3k rpm? ... when my MAF was bad, it seems to smooth out some over around 3k+ rpm ... not sure though, maybe someone else can confirm this?

And if you're using K&N, burn that crap ... go buy a dozen from joe . For some reason, my K&N makes my Q runs weird, even with a good MAF.

[maxnix]

Fuel Pump Control Unit.

Fuel Pump Control Module in the FSM.

[nchopp]

Took out the MAF, gave it a good cleaning (didn't look TOO bad) and she's purring like a happy (albeit very fast) kitty again. Thanks for the additional input, guys. :-)

[96Qowner]

It's a LOT more fun when it's running well, huh?

So, now you know it's the MAF. The cleaning won't solve your basic problem with it, though - it'll give you more trouble - maybe in the next few thousand mlles, maybe in the next few hundred. You should also clean the connector contacts real well, if you didn't do it when you cleaned the MAF. No one has given a definitive answer yet, but many suspect that the connector is actually what goes bad, and lets crap build up on the delicate MAF filament when the burn-off cycle quits working. I futzed with mine over thousands of miles, trying to nail down the exact problem, and finally broke down and bought a used replacement from car-parts.com for $75, when a cleaning no longer helped for more than a few hundred miles. It never stranded me, though - always would run, despite the occasional bucking and stalling.

Good to hear it was that simple.

[nchopp]

Yeah, just a bit. There's something just wrong about a car as elegant as the Q doing something as ridiculous as... stuttering. I'm planning on getting an MAF here in the next month or so, since it seems that's what it was. I'd JUST missed one on eBay for $50, so I can afford to be patient.