I own a 95 850 GLT sedan that has 221K miles on it. It just started this issue on Friday Morning. I'll be driving along and all of a sudden the RPM's will race up to 4K, at the same time the temp gauge will bottom out and then all the dash lights will come on. Then the car will lose power and nearly stall out.

I had a local shop check for codes and all that showed was a vacuum leak, but when they did a complete leak test there were no problems found. So what is up with this car? Does any one have any suggestions here. I need to fix this ASAP. It is my daily driver and I can't be with out transportation.

I look forward to the replies. Thank you.

Bob

If your ignition switch has never been replaced I'd give that a try. It's a pretty easy job with a couple of proper torx wrenches.

Yes the Ign switch could be the problem but I's suspect a corroded cable and or loose ground.

You should check your codes yourself, rather than relying on a generic scanner. There are codes for vacuum leaks, but only around the purge valve and that would turn on the CEL.

Your alternator is having problems? Or your battery ground cable is corroded and no longer grounding? When all of the dash lights come on, the engine has stopped! That is the reason for loss of power.

If you decide to clean the battery cables and posts and get rid of all of the white junk, make sure you have the radio code :)

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

Here is the latest on this 850. It is doing it on occasion still. Yesterday was a perfect day for it. The car is getting harder to crank over now because of it. But when it cranks over it has a rough idle for a bit. Then the temp gauge and tach will run normally. Then it will start to run funny. The temp gauge will go all the way back down and at the same time the rpm's on the tach will race up to between 2k - 4k range. Then it will nearly stall out.

Any ideas as to what is still causing this problem? I replaced the crank case sensor with a new one a few weeks ago, but that does not seem to be the answer. I just found out that I'm going to have to replace the radiator soon as well on this car. It is starting to show sign of aging.

I'd really like to get to the bottom of this problem soon. This car is starting to cost me more money than it is worth.

When is the last time you replaced the serpentine belt, the one that drives the alternator, PS, and AC? If it is wet and slips, you will have all of the dash lights come on. Does your car still have it's splash pan/air guide attached behind the bumper?

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

The Serpentine Belt was replaced this spring when I had to install a new alternator, PS Pump and AC Compressor unit. So it has maybe 10K miles on it at this point.
Yes my car still has the splash pan/air guide attached to it behind the bumper.

I just got a chance to check the error codes that show on the car at this point and they are the following:

1st. - 521 Oxygen Sensor heating faulty. This code has been around ever since I installed the new front O2 sensor. Not sure why. The new sensor was installed about 2 years ago.
2nd. - 241 EGR System Flow Fault.
3rd. - 123 Driver's Side Interior temp sensor shorted to ground.

How should I go about fixing these above problems. Sure would like to have a period of time that I'm not throwing money into this car. I need a serious cash break from it.

Look forward to the replies. Thanks.

The next time you see the temp needle fall, jiggle the key to check the ignition switch.
I don't have EGR on my cars, but I would check all the vacuum lines associated with it.
You may have not installed the O2 sensor wiring properly, or installed a generic sensor instead of a Bosh/OEM.
The cabin temp sensor is above your left shoulder behind the grab handle. Pull off the square plastic cover and check for dirt/lint buildup. Carefully clean it out with a toothpick and make sure you do not damage the thin metal probe in the center.

Recheck the wiring to the battery. Are the red wires hot to the touch after running? If so, they may be causing too much resistance and need to be replaced.

Yours is the first 850 I have heard of to have replaced all three of the motors on the S-belt. One of them may not be good and causing a strain on the belt.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

Hello,

Error code 521 is taken care of now. Installed new O2 sensor-Front.
Error code 123 is taken care of as well. Installed new temp sensor.

Error code 436 now comes up, but I don't have a clue as to what that is for? Any ideas.
Error code 241 comes back now as well, egr system flow fault. I quess I'll have to clean the EGR unit good to get rid of this code. Where is it located in the 850 Sedan engine compartment?

The ignition switch unit was replaced on this car last fall by me. The original unit was failing and causing all sorts of issues.
I'll check the vacuum line on the EGR system next week.
The Oxygen sensor is an OEM/Bosch replacement and has only one way of getting connected to the vehicle electrical system.
All cables to the Car Battery are fresh and very clean. The car battery was just replaced this spring as well on the car. So most of that area is clean and new.
The only reason why all got replaced is because the A/C Compressor unit was not working for the past 2 years. The alternator was not holding a charge any more and the power steering pump just out right failed one day. So I figured I might as well get all the parts once and do it once instead of seperately.

Any ideas on how to fix things?