For the past month or so my car has been misfiring whenever i floor it. I changed the fuel pump, spark plugs, and the MAF sensor. I have been told it could be my waste gate not working properly or the tune needs to be reflashed. Does anyone know what to do in this situation?

 

Going to need a lot more info to be able to help narrow down what is causing the problem.

Miles, year and trim are helpful, but I'm going to assume you have a 2008-2010 SS given the wastegate comment.

What spark plugs did you go with and gap?

What mods are installed on the car?

Is the ECU on a stock calibration?

Have you ran any blend of ethanol other than an e10?

 

My car is a 2009 Cobalt SS and has 145000 miles, i have the stage 2 package which includes a cold air intake, an intercooler, Upper hot side charge pipe, Lower cold side charge pipe, and a trifecta tune.The spark plugs are E3.66 plugs, i am not sure about the gap.

 

Gap matters.

The higher the HP, the more the boost, the tighter they need to be. Is it misfiring to the degree of the car breaking up real bad once it's in boost? If so, that's likely your problem.

 

Get rid of those plugs, the LNF is picky and seems to only really like AC Delco or NKG (essentially the same thing). Going with the AC Delco's you should be able to run the stock gap (0.035"), if you get the high RPM misfires then close the gap down to 0.032"

 

Yes onve it hits about 10 pounds of boost it starts breaking up.

 

98% of the time that happens, it's spark related.

 

And it is likely related to the snake oil e3 spark plug design. The LNF is not happy with plugs that differ from the OEM spec iridium and standard design.

 

Okay i will swap back to the other plugs, thank you for your help

 

Make sure the gap is 0.32 on the new plugs.

 

I just got the NGK iridium spark plugs with a 0.32 gap and the issue is still happening. I have tried the 0.35 AC Delco spark plugs and they didn't do any better.

I changed the fuel pump, that didn't help. I changed the coil packs and it didn't change.

I can't figure this issue out, is there anything else that I can do?

 

Try dropping the gap down on the AC's to .030", and see how it runs.

 

Tighten gap. If that doesn't work, check your vehicle's alternator output. Low volts/amps supplied to the coilpacks leads to reduced output. Shouldn't be the issue, but I've seen it be an issue.

If that's not the case, you might need to remove your injectors, send them out to be tested/cleaned, and put new seals on. One thing at a time though. Tighten the gap.