Any help out there would be appreciated. Sons car, overheated the other night, says it barely made it home, lack of power, he replaced thermostat, it started and seemed to run fine. Went to gas station, left there and 6 blocks later is looses power and dies. Note: it's not been running so good for quite a while but he has been living with it.

In troubleshooting we found one of the coil packs had a bad side to it and a bad plug wire. Replaced those, thinking those were probably bad for a while but don't really know.

We are getting spark, and compression is good. Smells like gas in cylinders do think the fuel pump is working. Tried starting fluid and got only backfire. Sounds good turning over like it wants to start. Thinking timing sensor or something like that. Oh yah we realized that the water pump is bad and that's why it overheated in the first place.

Any thoughts?

 

Is the check engine light on? Have the engine codes scanned. If its a sensor, you should get a code. Check the fuel pump pressure. If the pressure is low, it might run - poorly. If its too low, it will try to run, but won't quite do it.

There may be serious damage if the car was severely overheated. Aluminum heads don't take the extreme heat well. They may warp or crack.

The 3800 has a reputation as an excellent engine with good power, fuel mileage and reliability. One weak point is the lower intake manifold gaskets. The original gaskets tend to fail causing vacuum leaks and coolant leaks into the intake ports. I had driveability problems, intermentent check engine light and a slow loss of coolant. Changing the lower intake gaskets on my 95 Buick LeSabre (same chassis, engine, etc. as your Bonneville) cured these ills.

Good Luck!