'97 850 Throbbing Idle and 2nd gear "slippage" Topic is solved

dairyqueen814 · Post by **dairyqueen814** » 09 Sep 2016, 09:44

Hello!
It's been quite a while but I've finally got a problem or two I can't seem to figure out.

The car starts right up but once it does it chokes down to almost nothing and then comes back up, it levels out after a few chokes, but every so often I'll be at a stop light and I'll step on the gas, let up the clutch and almost stall out because the throttle won't respond right away. Also when the car is cold I'll shift into 2nd and it almost feels like the clutch is slipping as I bob back and forth, again this goes away after a few seconds of driving, and when I shift back down it wont do it again.

I'm wondering if it's my vacuum system but I checked the tree and so far nothing. I'm unsure of the rest of the places to check. I might also need to clean my PCV but I'm not sure if thats related. I did clean my MAF and reset the computer, cleaned my TB and my air filter. So far no luck
Any help is appreciated!

Nick

Adler · Post by **Adler** » 09 Sep 2016, 12:04

Wow, I just started having the same problem and we are both in Worcester. It would stumble at idle once in a while, just off idle, and sometimes going ~40mph around 2k rpm. Mine is an automatic and after it stalled out once today trying to merge on rt 9 I went home and checked all the same things you did. Nothing obvious yet, no codes, waiting for air filter to dry in the sun.

I'm going to pull the plugs and check the cap and rotor now. Just started reading a thread about checking MAF voltages while running.

Post by **polskamafia mjl** » 09 Sep 2016, 21:06

You can check the MAF by unplugging it and seeing if the engine starts running correctly.

dairyqueen814 · Post by **dairyqueen814** » 12 Sep 2016, 06:05

I just plugged in my OBDII and found I was throwing an MAF code. I just ordered a new one and I'll report back if it gets fixed. I unplugged the MAF and it ran the same. Not showing any voltage across the sensor so I'm guessing that's the problem.
@Adler I'm sure I've seen you around, I'm north of Worcester now but spent 2 years down there and I'm down in Shrewsbury every morning and afternoon. I always wave to other sweet wagons!
I'll keep an eye out!

Adler · Post by **Adler** » 12 Sep 2016, 20:23

I got my airbox stuff all back together after cleaning and fired it up. Started fine and idled normally while I checked the voltage at the MAF pin #4. It was steady around 1.1v so I went for a 20 mile drive and it was problem free. I took the car out again a few hours later and the symptoms came back after 5 minutes. This time I did catch the code with my scan gauge while driving-- P0171. I stopped and unplugged the MAF and no more problems! A new bosch is in the mail and I hope this solves it for good. I was thinking that it probably had a rough life because the airbox door flap was stuck on the hot side for a long time before I noticed.

@dairyqueen did you check the vacuum elbow at the intake near the belts? That one is for the PCV. It's weird that unplugging the MAF had no effect, maybe an air leak is hiding? I'm over on the west side and If you see a red wagon with a black spoiler, black volvo alloys, and PV544 mudflaps that's me.

Post by **abscate** » 13 Sep 2016, 04:39

P0171 is much more likely to be vacuum leak than MAF. There are lots of potential spots but the big one is the elbow under the intake manifold which is hard to see

dairyqueen814 · Post by **dairyqueen814** » 15 Sep 2016, 10:14

i just threw in my new MAF. still choking on startup but it runs smoother overall. the car has 150k on it and has never had it replaced. Ill hank on to it but ill check my vacuum lines under the mani. and report back.

Adler · Post by **Adler** » 15 Sep 2016, 23:13

New MAF fixed mine, resetting the ecu helped too. Make sure you check for cracks on all the pleats on the intake tube between the MAF and throttle.

dairyqueen814 · Post by **dairyqueen814** » 16 Sep 2016, 02:56

I did check that. My brother had a 93 850 that shot coolant everywhere because it overheated because of a hole in the hose. Car wanted to rev forever! Hahaha.
The elbow under the manifold is good. Does anyone have a vacuum diagram so I can start chasing gremlins? I was also thinking it could be the throttle position sensor. Might explain the intermittently unresponsive throttle. Thoughts?

dairyqueen814 · Post by **dairyqueen814** » 25 Sep 2016, 08:54

ALRIGHT LISTEN UP

After replacing the MAF, carbon canister purge valve, TPS, and tearing out my manifold to check the vacuum lines I found the answer.

One of the wires on the harness side plug of the MAF had been pulled out. After pushing it back in the car runs like new. Hope this helps someone out as I haven't seen anything referring to this on any forums! Good luck!