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gmdoctor1, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 9974
Experience:  Former GM technician
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1998 Pontiac Grand Prix will stall, RPMs drop to zero. Restarts

Resolved Question:

1998 Pontiac Grand Prix will stall, RPM's drop to zero. Restarts and runs fine however trac off light stays on. Next restart Trac off light goes out. Car seems to run fine. Happens on highway.
Submitted: 8 years ago.
Category: Pontiac
Expert:  gmdoctor1 replied 8 years ago.

Hello and thank you for using just answer. Do you have the 3.1, 3.8 or 3.8 SC engine?

DOes the check engine light ever come on?

How many miles are on the car?

Has anything been checked yet?

Customer: replied 8 years ago.

Hello, thank you for your expertise:


1. 3.8 LTR 3800 SFI V6 engine

2. Check engine light -not sure - I know the battery symbol comes up however after restart all goes back to normal except the trac off light stays on . Subsequent re-start then trac light off goes off and everything is OK.

3. 132,727 miles

4. Took to local shop and of course it did not act up all day. They thoughly checked battery and alternator ( 6 months old) are OK. The tighten battery terminals.


Problem as described happen today on highway. Do you think it is the crank position sensor ?

Expert:  gmdoctor1 replied 8 years ago.

Hello again and thank you for the reply.

Thank you for the detailed response, let me ask you one other thing before I start providing any information here.

-When did this problem start happening? (time and mileage)

Customer: replied 8 years ago.

I love my ponitac and I try to keep it in great condition. The problem started 4 weeks ago,

prior to that time it ran great. Have been afraid to get it away from home since that time as being stranded on the road is something I cannot do since I teach school. So the mileage since start of problem would be maybe 50 miles less than current mileage.


I appreciate your response.


Expert:  gmdoctor1 replied 8 years ago.

Thank you for your detailed replies.

From your initial question I had about 7 different things that came to mind, yes a crank sensor came to mind but I eliminate that based on your replies.


Everything on this car is controlled electronically, either uses battery voltage, sends a signal based on voltage ot resistance or completes a path to ground to operate.

Your traction control/ABS system is a system that is VERY sensitive to voltage. If the voltage is not perfect it shuts down and causes a indicator light as you describe.

You stated you alredy had a mechanic check the car, I will assume at this point that he connected a scan tool and checked for codes related to inputs sensors/etc...that would have caused this. So let's eliminate sensors/etc.....

Fuel pressure is not likely, if the car suddenly shuts off and will restart with no issues at speed then pressure is not dropping.


I'm thinking voltage at this point. Either you have a loose connection, corrosion or an voltage issue from the battery or alternator.

If the battery terminals are both clean and tight, the alternator connecions are good and no issues found with corrosion then lets move on. The battery needs to be connected to a battery analyzer, not just volt and load testing, a full dynamic scan. Same for the alternator, they commonly fail on these cars and have a regulator built in. You are most likely going to find that the alternator is intermittently acting up here baed on your inputs and comment of battery light coming on. Personally I recommend a genuine ac delco alternator, aviod remanufactured aftermarket units on this sensitive car.

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