1997 850 NA stalling when put in drive in cold weather

lizards · Post by **lizards** » 20 Dec 2022, 17:53

My 97 850 NA 104k miles has been having a hard time in the Chicago winter. In the summer I have no issues. But now it's below freezing I have had an issue when putting it in drive.

In the winter, it starts no problem, goes in reverse no problem, but as soon as I put it in drive it stalls and shuts off. When I turn it back on I can put it in drive without it stalling. I always wait a good 5 min with it idling so it can warm up, have a scan tool and temp reaches at least 150°F before I put it in drive. After I have been driving it and I'm gone for some time I can start it up and put it in drive immediately with no issues. It only happens the first time I drive the car that day. It's parked outside on the street so it's in cold weather all winter.

From the last 1.5 years: Fuel pump has been replaced, pcv serviced, new plugs, new cap and rotor, new plug wires, regular oil changes as well, less than 3k miles over the last 1.5 years as well. The air intake is coming from the pre heater hose and I cleaned the MAF as well. Driving around the city I get 15-18mpg short distances. Haven't taken a long drive in a while but last year a 3 hour drive was around 24mpg.

From some other posts I saw the fuel pressure regulator could be the issue, but I don't have any black smoke coming out, just a lot of the normal winter exhaust.

454cid · Post by **454cid** » 21 Dec 2022, 00:59

What's the computer say the engine coolant temperature is, when you first start it? Is it air temperature or much different?

lizards · Post by **lizards** » 22 Dec 2022, 08:05

Unfortunately I use the scanguage 2 and the air temperature was not reading. Unsure if this is a MAF issue or if the scanguage 2 can't read air temperature in these cars.

This morning when I started the car the coolant temp was 32°F and outside temp was around the same. I timed how long it takes to go from 32° to 150°F and it took 5 and a half minutes. I had the car in sport mode and surprisingly did not have an issue putting it in drive.

Post by **bmdubya1198** » 22 Dec 2022, 09:15

I believe the scan gauge can monitor fuel trims, can you view the short term fuel trim before you get it to stall? I have a feeling the coolant temperature sensor may be failing.
It may also be a good idea to check the fuel pressure on a cold start to make sure it's within spec. I'm leaning towards some sort of fueling/temperature issue though, being that it's only when it's cold that this happens.

lizards · Post by **lizards** » 22 Dec 2022, 09:57

Thanks for the reply. You're right the scanguage 2 can look at fuel trim as well as fuel pressure. I'll report back tomorrow morning, gonna be single digits so good conditions to test.

For coolant temperature sensor failing, would I see any other symptoms related to it? the gauge stays at 3 o'clock when at temperature, and scanguage keeps it 180-200 when driving

Post by **MoVolvos** » 22 Dec 2022, 14:30

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Since the car starts fine and reverses but only stalls moving forward when cold try a transmission fluid drain and fill. With that much work already done and nothing has changed it's worth a try. If it improves even a little may want to do a complete fluid exchange. Could also be a combination of electro-mechanical related to the transmission other than fluid alone.
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Post by **bmdubya1198** » 22 Dec 2022, 17:19

The temperature gauge isn't typically affected by a failing temp sensor, however the fuel mixture being out of whack is usually the main symptom of failure.