Car dies, only after traveling at higher speed

oldsmobile
ninety-eight

#1

After being on the expressway, the car wants to die when I exit and come to a stop. It surges and then dies. When I restart it, if I put it in gear it dies. My mechanic has checked all the hoses, gas line etc and can’t find the problem. It conveniently won’t do it when I take it to him. Otherwise the car runs great, this problem just started.


#2

Do you have a temp gauge? If not it might be worth putting one in as my first guess is it is overheating. The cooling system can’t keep up with the high residual heat after high speed driving, I had that happen with one car, and it was not hot enough to set off the idiot light. The temporary solution was to drive a couple of miles at low speed to deal with the heat buildup.


#3

Try unplugging the connector for the torque converter lock-up clutch solenoid.

Sometimes these solenoids will stick and won’t release the torque converter clutch causing the engine to stall. Then when you restart the engine and put the transmission in gear the engine stalls.

This is like coming to a stop with a manual transmission in 4th gear without stepping the clutch pedal. The engine will stall. And if you where to restart the engine and try to take off in 4th gear, the engine would stall.

Tester


#4

If your vehicule is equipped with a TPS (THROTTLE POSITION SENSOR) you might have a defective or dirty sensor. A special spray cleaner is needed to clean it.


#5

Good ideas above. If those don’t pan out, another idea, it could be running too lean at that point for some reason. Or just not enough air is getting into the engine, the throttle valve is shut off too much. When you take your foot off the gas and coast (in gear or not) the intake manifold vacuum rises and that force could pull the throttle valve to a more shut position that it normally is. You’d usually notice the idle rpm was lower than before, but sometimes that can be subtle from inside the car. If it is the throttle valve problem, usually the sol’n is to remove the throttle body & give it a good cleaning on both sides. PCV and EGR systems can gunk it up over time. If you could measure the idle rpm (in neutral) just before this happens, compared to when it doesn’t happen, that might be helpful to the shop tech who’s doing the diagnosis.


#6

What year?
How many miles?
What engine?

The Ninety-Eight was produced from 1940 to 1996 (minus the war years of '41 to '45).
Knowing the year and engine would go a long way toward identifying the possibilities. Both fuel systems and ignition systems changed greatly over the lifespan of the Ninety-Eight. Fuel injection, in the form of throttle body injection, didn’t become commonplace until about 1990.


#7

I had a motorcycle that would die after a full throttle high speed pass. I fixed it by opening the stopped up air vent in the gas cap.


#8

I can drive low speed at that point and it not die - if I come to a stop extremely slow.
Thanks for your help.
It’s a 1982, 180,000 miles, no other problems.
I have taken the gas cap off to no avail. The mechanic initially suggested this.


#9

Thank you, I will give this to the mechanic.


#11

Open throttle and clean inside of throat. Especially behind where throttle blade stops. It looks clean when you look inside with throttle closed. But open throttle and clean everything.