- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
there is detail missing here that is essential for a solution
what engine is it , v or straight, no of cylinders
what work has been done prior to the problem
what ,make and model, year of vehicle
you have changed spark plugs so assuming it is a v8 I would be rechecking the firing order of the HT leads ( 2 cylinders crossed )
They will start and idle ok but backfire under load
po300 is random miss fire doubtful two O2 sensors bad at one time most likely coolant temp sensor is bad causing engine to run rich this will cause O2 sensors to throw a code(thats what they are there for..exhaust gas temp. and raw fuel) running rich will also fowl spark plugs(=miss fire) P1128 ??
Could only be a few things. The coil #1, Fuel injector #1, Stuck intake or exhaust valve, or blown head gasket allowing coolant into cylinder #1. Use a spark tester to check the spark coming out of cylindr #1 if checks good then ohm test the injector when it is warm. Check other injectors to compare. Do a compression test on cylinder #1 and test other cylinders to compare. If cylinder is low compression suspect valves and or head gasket. If compression is low then het a leak down tester to test if a valve is broke or sticking. On your sable i would suspect injector or coil most likely.
The easiest thing is to make sure the firing order is correct with the spark plug wires. You may have 5 and 3 spark plug wires crossed. Also, was this vehicle running ok before the head gasket repair???
Do you get black exhaust smoke when first started? If so, then there is too much fuel at first which probably fouls several spark plugs, but as the engine warms up, the plugs start firing again. If no black smoke--is the check engine light ON? Read the code(s) if so and follow the clues.
black smoke is usually fuel...white is usually coolant...you may have a warped cylinder head or some other mechanical problem. do a compression test. If you disable the #2 injector does smoke continue? if it does, it's not fuel. When you remove #2 spark plug, is it wet? if so what's on it?