Intermittent stalling/rough idle/MAF Sensor error code | 1994 850

fuZzzmuffin · Post by **fuZzzmuffin** » 05 May 2025, 23:00

Hey everyone,

I've been lurking on here for a while now and found a handful of posts with similar issues, but there are some things that seem specific to my situation, and I figured I'd post here before I start ripping out parts.

My 1994 850 has been having stalling issues for the past 6 months or so. I'm pretty sure it only ever happens after warming up, and it's usually worse towards the end of the day (after sitting in the sun all day). When the idle drops and it starts to stall, the low oil indicator light starts to flutter on (I recently got an oil change, so that shouldn't be an issue). When it fully stalls, all of the dash lights turn on. This only ever happens on idle/low RPMs (luckily never at highway speeds), and I can mitigate it by lightly stepping on the throttle while braking. It usually starts up fine after stalling, but every once in a while there's some hesitation while turning over.

I've taken it into the shop multiple times, they've replaced the MAF sensor, they've cleaned the new sensor, they've cleaned the battery connectors, but the stalling issues are still present (and the MAF code keeps coming back). After getting my car back from the shop the last time, I found out that they'd sheared off the little jack that connects to the diagnostic box, so I can't check or clear codes until it's replaced. Out of frustration and desperation (because I love this car, but I don't have the money to keep taking it into the shop), I've decided to try fixing it myself. But I have to do it soon because my registration deadline is coming up and I have to pass smog this year (my timeline is about a month).

If anyone has any input they'd be willing to share, I would greatly appreciate it. It would break my heart to have to retire ol' Grendel.

Thank you for your time!
-fuZzz

Post by **abscate** » 06 May 2025, 03:41

Your 1994 has an idle air control valve that gets dirty and needs cleaning on occasion. That’s where I would start

The lights coming on at low rpm’s is all normal and not indicative of any problem.

What’s the MAF code that pops up? If it’s running rough, that might not be a “ real code” just a spurious one.

Post by **jreed** » 06 May 2025, 05:30

I was thinking the same thing... it could be the IAC / idle air control valve as listed above. My car does the same thing when the IAC is dirty and it gets very warm out.
I wrote up some more info about how to do the cleaning here:
viewtopic.php?t=47533

jmartin919 · Post by **jmartin919** » 06 May 2025, 06:20

I would look real close for cracks all around the corrogations on the plastic pipe just after the MAF sensor.

fuZzzmuffin · Post by **fuZzzmuffin** » 06 May 2025, 23:11

Thank you all for the quick responses!

abscate:
I'd seen similar posts referencing the IAC, but I wasn't sure if that would be the most likely culprit in my case. Thank you for confirming! And the error code is 1-2-1 "MAF sensor signal" (A2 - Fuel System). At least, historically, that's what it's always been. I have a replacement diagnostic box coming in the mail (part #3545006), so I'll be able to confirm after it's installed.

jreed:
Thanks so much for linking your tutorial! I'll make sure I have throttle body cleaner and new hose clamps on hand.

jmartin919:
I'll give that section a thorough inspection for cracks and see if I can source some replacements if I find any. Thanks for the head-up!

Post by **jreed** » 07 May 2025, 05:30

Good luck with the repairs and troubleshooting and please let us know what you find out.