i have 1995 buick lesabre custom have replaced the ignition key cylinder with new keys reprogrammed, replaced the ignition control module and the crank and cam postioning sensors based on the computer codes received. the car drives great and then suddenly it dies as if someone shut off the key, occassionallly prior to shutting off there feels like a boost occurring from the rear , the speedometer jolts forward about 20mph and then the dash lights come on and the car stalls puttting the car in neutral and it will restart. but need help in locating the problem spent too much money thus far, help

 

When your car did this ? When you drove on highway ? in town ? at high
or low cruise speed ? or when you want to make a stop ?

 

The started doing this only on the highway but now does it around town or when stopping. It is a ramdom thing and the fuel filter was changed as well. Any ideas?

 

it also doesn't seem to do it when the weather is colder as much as when the weather is warmer or after the car has warmed up.

 

It's look like a defective EGR valve, this valve does'nt operate until the car is warm and can cause your trouble.



You can try to unplug it, on your car it's certainly an electric one.
Your Check engine soon light will lite on (because the valve will stay
shut off all the time) but don't bother with this.

 

thanks for the advice gave it a try the problem was worse with the engine cold but now when it is warm it runs fine any suggestions

 

You have unplugged the valve and now you're car run fine when hot, your
EGR valve must be leaky AND have a defective actuator (the electrical
part of the valve). By unpluggin it you have bypassed the actuator bug
but because it's leaky to many exaust gas return (EGR) to the motor,
when cold the motor need more fresh air. When plugged the actuator help
to keep the valve sealed.



I think you should install a new EGR valve.

 

HI I HAVE INSTALLED THE EGR VALVE AND FOR THE LAST 3 DAYS THERE HAVE BEEN NO PROBLEMS THANKS ALOT FOR ALL YOUR HELP YOU SAVED ME ALOT OF MONEY ONCE AGAIN THANKS ALOT