99GT Sudden Problems

This is a 99 GT, 100K miles

In this thread of a few weeks ago I described the Trac Off lamp coming on under unusual circumstances:

http://www.automotiveforums.com/vbulletin/showthread.php?t=263795

I did not tear into the dash to check the Track switch, but did follow the other advice provided at that post regarding connections at the ebcm - could find nothing wrong.

A few days after the above post, the engine started to occasionally die, or almost die, as if someone had turned off the ignition for a split second. This happens at idle, or while driving at slow speeds, with the engine at operating temp. (It doesn't idle roughly or hesitate - the engine runs smoothly at all times.) In every case where the engine died it would start right up. No SES light, but occasionally the Track Off lamp would come on upon engine restart. (At this point, if I turn off and then restart the car, the Track Off lamp remains off.)

Now, this the "best" part - today, when I arrived home, I turned the AC fan switch to off at which point:

1.) The Tach went to exactly zero (not below zero where it points when the engine is off) and stayed there
2.) The Track Off lamp came on
3.) The SES light came on for a second, then went off

The engine continued to run smoothly while the above was happening.

I turned it off and restarted, and everything was normal again.

I took it to Auto Zone to have the codes read - no problem codes present (but the engine did cut out in their parking lot!).

Are all of these things somehow related? I would think that they are since they are new issues over the past three weeks. Or is the car merely posessed?

BTW-the car is pretty well maintained. Air and fuel filters have about 10k miles on them, regular oil changes, etc. Also, the Mass Air Sensor was replaced at approx 93k miles, the PCM was replaced under warranty at about 45K miles.

Thanks to any and all for your insight.

i dont think i was having the EXACT problem you had but i had one where i would be driving and then all of a sudden the car would sound like it's choking itself but very fast then the tach would go to 0 but not all the way down and my trac off light would come on. well one day when it did that it finally threw a code. it was for a crankshaft position sensor that had gone bad. i had it replaced which cost me 200+ bucks b/c of it's location (behind front right tire somewhere) after that fix it has never occurred since. so i dont know if you wanted to look into that kinda thing? just trying to get some ideas.

hope this helps, Rob

Your crank sensor is located behind the harmonic balancer on the front of the engine. It requires the removal of the balancer to change. From what you describe it points to the crank sensor. Sometimes they will intermittently fail and not trip a code.

Just got an SES light - looks like it finally threw a code. Will see what's up and report back. Thanks for your input and suggestions.