1998_trans_am_ls1

iTrader: (5)

Didnt know where I should post long story short.
About s week ago I installed my pacesetter LTs and ory ever since its been misfiring checked all plugs wires and everything regapped the plugs to what everyone on heres running them right around 50 and it's still misfiring . My question is the rear o2's arnt hooked up yet could this be the problem? If so I'll run and get the parts to hook them up if not what else could it be? My coils should be fine never had this problem before

1998_trans_am_ls1

iTrader: (5)

When I plugged it in to my hypertech it just read misfire and o2 sensors I don't remember the numbers off the top of my head I believe 300 may have been one

Nathan C

After installing headers you need to get a tune, but it shouldn't be running that poorly. Plug in the O2 sensors and see what happens.

US_Army_Z28

iTrader: (3)

The rear o2s are simply there to monitor the exhaust gasses after the cat to make sure the cat is doing its job. Wouldnt cause a missfire i have only front o2s and no tune and my car runs like a champ. A tune would be good after a header install but is not 100% necessary. You just wont get all you can out of your car without the tune. I would check the coils

Tyrel2018

iTrader: (8)

well if its a p0300 its a random multipul misfire code, so either you didnt plug the coils back in after unplugging them or there is a ground off somewhere. there are other things that could be wrong too. i had junk plugs and it made my car run like crap. did you change the plug gap during the header install or after?

ls1sickandtwisted

I had the same problems when I installed my headers I had the 02 sensors codes on for the rear but I knew that since I was deleting cats I also had misfire codes but my mechanic check I bought new msd wires new spark plugs and still the car ran fine so I used it until the day I had to take it the tune shop I mention it to the shop the issue after the tune it was all good no more codes no more misfires o asked and they told me after bolts on the car can run richer or leaner and cus code or react like misfires I'm not sayin a tune will fix it it just what happend to me

Blownbayou

iTrader: (7)

fwiw..... I installed my tr5s with the old gap .059 Wonder if the header is heating up the plug wire??? Stock wires????

1998_trans_am_ls1

iTrader: (5)

I have checked the wires there not touching the headers. Turned car on at night didn't see any spark outta the wire do I think wires are good

Blownbayou

iTrader: (7)

how many miles on the wires???

ls1sickandtwisted

Another thing to look at is if there's no air leaks on the headers? What kind off gaskets u used? Check for the headers for air leaks

LunarWillow

iTrader: (3)

A question for you: Did you by chance remove the spark plugs when doing the install? Reason being, if you didn't, then there's a chance the headers might have bumped them during install and caused the porcelain to develop a small crack, which could definitely cause your misfire.

1998_trans_am_ls1

iTrader: (5)

I did put In brand new plugs during install and checked again after the install there was no crack. I checked the front o2's today and they are good where else can I look? A few buddies and a tuner I talked to said I may need a tune. Idk what else to do any more feedback would be helpful.