bornrich

I'm experiencing two issue they may be related or not. First I'm having intermittent stalling issue. After a long run on the freeway and them slowing for an off ramp or signal the car stalls. I can restart it just fine, but this is unnerving.

The second is a more recent issue. I was driving home from work on Friday, weather in the mid 80's, traffic started to back up. My temp gauge started to rise. Usually it resides between the 180 and the first white tic mark. It slowly rose past that tic ( I then turned of my AC) and it continued to rise until
the needle was about half way between the that tic mark and the red 250 mark. When i noticed this and I saw the traffic wasn't going to thin anytime soon, I put the heater on full. This lowered the temp back to just under the white tic. Still warm but not rising either. Also at this time the idle started
to fluctuate from a little 1k down to almost stalling. I got the car home with out any further issue other than the temp being a little high.

Now yesterday I was driving home from the track and I was in city traffic, the car started to get a little hot nothing too bad just a little below the white tic
after the 180 mark on the gauge. My idle stared fluctuating once again. This time the car stalled when the idle dropped too low. Now I was paranoid and I
tried to keep the revs up at stoplight to avoid the stall. one I got back on the freeway the were no further problems. I going to bring the can into
my Indy shop to run some diags. Anyone have any experiences like this?

Macster

A '99? That's pre e-gas, IIRC. Thus for idle issues I'd consider the idle control valve. Dirty or going bad.

But do not ignore the possibility of a failing AOS either.

For the apparent overheating problem be sure both fans come on at least low speed when the coolant is hot enough. My info is the fans should come on at 212F and shut off at 205F.

With a '99 I believe through some finger hocus pocus at the A/C controls you can call up the coolant temp (among other things).
There's a document that describes how to do this here or there. If you can't find it send me a PM and I'll respond with a copy I have on my PC's hard disk.

Just in case too, with the car dead cold and on a lift start the engine and let it idle while you then get the car in the air and as the engine runs and warms up feel (carefully!) the hoses to/from the water pump to ensure the t-stat opens and the pump pumps coolant and this at some point warm coolant flows to the radiators and back again.

While you are under the car carefully check for signs of coolant leaks. Do this with the engine off! Check the water pump, the bottom of the tank, where the hoses connect, the radiators, etc.

Oh, until you get this all sorted out I'd stay away from the track.

bornrich

Thanks for the quick response. Yes this is a non-egas car. I will look into the idle control valve but the idle issue seems to only happen when the car is warm/hot.
I wasn't tracking the car, I instruct and thus spend most of my time in other people's cars. I did drive it up to the track to see how it behaved. The car didn't get really warm on the trip up and I even tried a parade lap at lunch ( 25-50 MPH) with no issues at all. There were no leaks I could detect either when hot nor cold the next day.

Ahsai

Re the water temp issue, were the water pump and thermostat ever replaced? I assume the coolant level is good?

bornrich

As far as I can see from the records that came with the car neither the water pump or the thermostat has been replaced. I going to have those replaced regardless. And yes the coolant level has been constant with no visible lose of coolant.

Ahsai

That would be a good start. Inspection and replacement in one shot.

Imo000

Besides checking the fans, have a quick look to see if the radiators are clean.

thedugger1

Had the same issue on the temp. Turned out that the driver's fan was dead. It seems that unless it gets really hot, the passenger fan is sufficient, but with temps increasing I noticed it was also running hot until the a/c would shut down. Just swapped it out last week and it's perfect now.

bornrich

I cleaned my rads over the winter, so they are good. I will looking the fans too.

Ubermensch

Definitely my first guess on the rising temperature is a dead fan or resistor that controls high/low operation of the fans. Make sure they both come one low and both cycle to high. Just because it runs on low doesn't mean its working on high.

bornrich

The car is at my Indy shop to investigate my idle/stalling issue. I will have them check on the fans.

LordVicious

just to save Mac the trouble ... Hold down the Recirculating & Air up buttons for 5 seconds. The + - buttons go up and down through the list of "c" codes. The center vent button switches the left display between the "c" code and its actual value. Press the Auto button to exit. I typically monitor code 6c, coolant temperature.

This will give you a MUCH clearer picture of coolant temperature, which will probably scare the **** out of you (at first.) Long story short, the coolant temperature can spike very high, very fast when the engine is heat soaked. This is normal and will not trip the temperature warning light.

THIS PART IS VERY IMPORTANT, if the temperature warning light comes on shut down immediately. If the computer didn't throw a warning then I suspect your cooling system is operating normally.

The stalling issue is probably coincidental. Plugs, AOS, fuel pump ... all have been mentioned. Since your tracking the car, well, you know, **** breaks

bornrich

Thanks for the info! The temp warning light never came on and I would have pulled over and stopped the engine. I know track the car will accelerate wear, but the overheating (over-warming?) is more likely a failure that would have happen even if I never tracked the car. I'm used to air-cooled cars so I'm hyper-sensitive to engine temp. My intention is to be careful with my maintenance and be sure to have all wear items replaced before they fail.

bornrich

Update:
WP and Thermostat replaced as requested. Found drivers side fan was not functional. Still trying to find the stalling issue.