Questionthe car has been running rough then service soon light came on,then started stalling when under a load replaced the hall effect switch disconnected battery then test drive light is out doesnt stall but still idling rough
AnswerHi Jane,
Not sure why you would want to replace the hall effect switch...was the code you got a P041?
Rough running can be caused by alot of differant things on your car. The obvious being a need for a tune-up which consists of A/C Delco sparkplugs, sparkplug wires, distributor cap and rotor, air and fuel filters and a PCV valve. If you see a burn mark on the black plastic of the ignition coil then it should be replaced.
There is a problem with the battery negative cable getting corroded and the engine will run rough or quit altogether. It gets worse the more amperage is needed like when the head lamps are on, blower motor on high, rear defrost is on etc. The fix is to remove the cable and clean the end with fine sandpaper like 200 or higher. Also sand the engine block and both sides of the starter bracket and then bolt everything back together. Even if it looks clean do it anyway because unless you test the connection with a voltmeter it could look clean but really be a problem.
Fuel injectors of which you have 8 are known to short and cause rough running. The way they act up is when the engine is started cold it might run ok but the hotter the engine gets the worse it will run. In extreme casses I have actually had 5 shorted injectors and the engine still ran. However it is reccommended that you replace all injectors if 3 or more test bad.
If you disconnected the battery or engine computor there is a relearn procedure that needs to be done. Also Carbon could be building up under the throttlebody plates and that would need to be cleaned. There is a special procedure to check and adjust the timing, idle speed/minimum air, throttle position sensor/TPS, and idle speed control motor/ISC. If those are off then the engine could idle slower/rougher.
Then there are some computor sensors that if not working correctly could cause a rough running engine. Such as the TPS, manifold pressure sensor/MAP and oxygen sensor.
Fuel pressure needs to checked so it isn't too low.
As you can see there are alot of things to check. I would start with the tune-up and cleaning the negative battery cable first and see what happens. Hopefully that will solve the problem. If not start going down the list or have your mechanic check it out so you know what to replace. Let me know if I can be anymore help. Bill
