Hello all,

I need your collective help on tracking down an intermittent problem. My 96 850 (nonturbo) occasionally surges a bit. It happens only when the motor is warm, at a speed of about 40 mph and at about 2100 rpm, when driving up a hill at constant speed. What happens is the engine briefly races up to about 2400 rpm. There is no surge in the car itself, just the engine. It then drops rapidly back down to 2100 rpm, accompanied by a "slam" feeling that feels about the same as a very hard shift in the automatic transmission.

So, is this a problem with the transmission, or a problem with the engine (computer, 02 sensor, throttle sensor or something like that?)?

Thanks for your help!

Rich R

Richr,

I had the same problem 95 855 non-turbo. When it first happened, I was also driving at constant speed 35-40 mph, rpm rev. up and felt the "slam" from the gas pedal. The "slam" was actually from transmission unit. Transmission unit couldn't determine which gear to shift in. The problem got worst in 3 days, and transmission couldn't lockup at highway speed driving. When dealer first looked at it, they told me a new transmission. Dealer replaced the transmission, but the "slam" still exists at constant speed driving (uphill). Dealer checked the car again the second time, no fault code stored. The master tech. was then test drive my car with me. I told him the way to duplicate the problem. He did, but still didn't know what went wrong. I then got a response in this forum regarding to the throttle position sensor failure. I told the dealer and they replaced the TPS. Problem went away.

Replace the TPS fast or you need a new transmission soon.

Ching-Ho Cheng

i had the same problem with my 95 850. i took it to a reputable shop and all codes were good. finally when it occured again i took it back to the shop where they ran the diagnostics and found it to be the throttle control unit. i had it replaced and it fixed the problem...only issue now with my car is that the check engine light remains on with clear codes. good luck.

I have this exact problem as described. I am getting a fault code 2-3-2, but I think it is the same problem. 35-40 mph and zooming to 3000rpm. I have tried to isolate this for a year. Is this an easy repair for me to do.

Also did anyone have this problem, accompanied with a higher idle in park. Hot or cold my engine races to 1500 rpm in park. I still think this is the same problem.

Thanks for the help, you guys are terrific.