I have a 2001 Alero, the car started idling very rough, got the code pulled, had 300 - Random Misfire, took to shop, they replaced the Plugs and Wires, still doing it. Replaced the Fuel control Value/Sensor, and now the car starts immediately, and Runs great when giving gas, but when Idle still get a Misfire on Cylinder 1, pulled code again and it is 301. They had the computer on it and was watching it misfire when idle, but when you give it gas, the misfires stop???
They tested the Injector, by turning it off and on with the computer, and it was working.

Have now replaced the Wires, Plugs, Fuel Control Valve/Sensor, Idle Control Sensor, and the Coil pack for the 1/4 Plugs. $500.00 dollars so far

ANY HELP PLEASE????

 

Not a lot left but the injector, is there? I would have guessed coil pack, but since that's new, I would swap the #1 injector with another cylinder to further troubleshoot the problem.

 

What spark plugs did they put in? Did the shop check the ignition module?

You should have posted here before you spent the $500. Trouble shooting a misfire is pretty easy. You could have swapped a plug from one of the cylinder that wasn't misfiring into the one that was. If the misfire moves from the one cylinder to the other its a bad plug. If the misfire doesn't move, move on to the plug wires and so on.

Did the shop check the injector pulse width( how long the injector stays open)? If it is open too long giving that cylinder too much fuel that could cause a misfire also. If you check everything(plugs, wires, coils, ignition module, and injector) and everything is working fine you may have a head gasket that is allowing coolant into the cylinder. I hope this isn't your problem though, its pretty expensive.

If is your ignition module I have a spare one that I will sell you, I'm sure you don't want to spend $360 for a new one. Or if you have a junk yard around your area you can get one from there.

Hope you get it figured out.

 

Going to try to replace the plug tonight and see if that solves it. But if not, where is the ignition module, how much will it cost to have it checked, can autozone or somewhere like that do it? I know I have a lot into this so far, but to start it was misfiring on most cylinders and would barely run, themn they replace the plugs (Delco) and the Wires, that solved some of it, but then it was surging and hunting for idle, and they said the Fuel control needed to be replaced, so they did that, and then it was only misfiring on Cylinder one. They said they tested compression already, so hope its not the Gasket. Thought maybe the plug in 1, could have gotten fowled out from the fuel control dumping to much or something and hoping. If the plug doesn't fix, should I go after the Injector or look towards the ignition module you spoke of?

 

The ignition module is what the coils sit on. I'm not sure if autozone can test it or not. Just ask them if they can before you go through the trouble of taking it off.

Its hard to say which one it would be. Do you know if they saved the results of the scan they did on the car.

 

Was able to get his fixed, when the shop had out in the spark plug on Cylinder One they had bent the top of the plug down and was causing the issue. Bent back into place with pliers and put back in, Purrs like a kitten now.

 

Right on! The easy cheap fixes are the best ones.