I have a 99 benneville se and the check engine light came on. I scanned it and i got the p0301 misfire cylinder 1. I replaced the plugs and wires I then erased the code to see if it would eventually come back on but it has not. My car now is sluggish and just does not want to get up and go. It also sounds like i have a vacuum leak. Help plz

Please put your car'* year and model into your signature line (User CP at top of this page, Edit Signature in menu on left of page that opens up) so we can best address your questions.

Is your car supercharged?

If you suspect a vacuum leak, get a spray can of carb cleaner and spray it around the vacuum connections, the EGR, etc. A change in idle speed when you spray an area is a sign of a vauum leak, and will help you focus in on it.

no its not super charged and i already tried the spray and couldnt find any

https://www.gmforum.com/t280296/

https://www.gmforum.com/t279319/

https://www.gmforum.com/t278926/

so you think it could be one of those sensors? but i dont have a ses light on or does it just come on when the sensor is completely bad?

Pull the plugs and look close. Are any of them black? If so you have a combustion problem due to weak spark.

i replaced the plugs a few were black.

You should still use the procedures I posted earlier, but you should also check your ignition coils.

https://www.gmforum.com/t278818/

The black ones have a weak spark. That comes from a weak or bad coil, bad or weak plug wire, or worn plugs.

I tested the coils and everything was fine with them. I guess im just stuck on how my car wont get up and go and is so sluggish. No ses light comes on either.