i just installed the flowmaster exhaust kit on my car and 2 days later my car started spuddering what could it be

 

Hmm. It could be a number of things. Tell us a little more. Does it do it throughout the driving range? High or low RPMs? Feel like it's lost power, only act up under load, etc.? Also, is the Service Engine Soon light illuminated? If so, does it blink at any certain time?

 

the service engine light just came on it says missfire in cylinder one and o2 sensor its mostly at low rpms and under heavy loads

 

What's the exact O2 sensor code? Take your number one plug wire off and inspect it for cracks, weak spots, and brittleness. Any burns or blemishes should indicate that it's time to buy a new set and install them properly. I'd also take out the number one spark plug to make sure it's clean, and that the electrode is not unacceptable. I'd also check the gap. I'd then swap the coil pack that fires number one with the one next to it, and then observe if the misfire follows the coil pack. If so, replace the coil pack.

I'm very much willing to bet that it's an electrical problem, like most hesitations and misfires. Hope this information helps. If all else fails, take the car out at night, headlights off, engine running, and watch under the hood and around the manifolds for a spark. Have a friend push the accelerator. It's possible a wire is shorting out somewhere, however, it may be hard to detect this since the engine is not under a load when it's in park or neutral.

Hope this helped!

 

yeah this is the third time this has happend to my car each time i brought it to the dealership cus it was under warrenty i have all new plugs and wires the fuel pressure regulater was junk and so was thefuel pumpafter all that was doneitrangreat for 7months but ill take a look for arcing andcheak out that plugi dont remember the exact code ill have to cheack it agian on tuesday but you dont think that the new exhaust would have caused this?

 

Honestly, no. It should not have any effect. I actually have the same system on my car. No problems to boot.

 

The exhaust won't make the car run poorly, but you could have disturbed some electrical stuff, including the plug wires, and some wires may even be touching the hot exhaust.