This may seem like a rather lengthy read but please bear with me. My wife owns a 94 Bonneville that she bought from her parents. Her parents had the same problems with the car but now after a few years the problem is worstened. I will try to explain everything and I ask for your opinions, trials and tribulations.
The car to me drives if it has a clogged catalytic converter ( best explanation). It bogs when you give it gas, at any speed, and stutters when taking off. Also it takes awhile to get up to cruising speed. If , when braking, I keep the idle at 1500 rpm and take off the stuttering is not present but all else is. The best way to get up to speed is by lightly applying gas pressure. Sometimes while getting up to speed, if you let off the gas you increase speed better.
Okay......now that you think you got it let me get on with the rest.
When her parents owned the vehicle, nearly everything under the hood was replaced including the ecu. The only thing that was never replaced by them was the fuel injectors, which I recently did myself with refurbished/cleaned injectors.
None of these things have done the trick. Another thing I need to add is that we recently took the vehicle for a diagniostics test by a dealership, and our backyard mechanic, whom is also a very good professional mechanic by day. What the dealers comprehensive test shown is that our car is perfect except the ecu. Our personal mechanic used a MAC TOOL diagnostic tester and his also pointed out the ecu.The code his tester showed are as follows....p 1406, p1670, and p1640. The 1406 is because the EGR is not responding properly to commands from the PCM. The 1670 Is the drver 4 and the 1640 error is for the quad driver module.
Our solution.....buy a new one. Her father paid $1200 for an ecu when he replaced it and that didn't repair the problem. We paid $130 3 weeks ago and this didn't solve the problem so we returned it. Yes, you heard correctly.......don't mess with a po'd scorpio woman with car problems.
Now with that all said, several people seem to think that it may be due to bad electrical. Also, the wife found another read that sounded identicle to what her problem is and they replaced the booster control solenoid and the problem cleared itself.
Let me know any suggestions or testimonies please. Thanks. Bummed out hubby of a Bonneville owner.