Big problem after header install. Need Help!
Big problem after header install. Need Help! I just finished the header install and the car was running fine for a while until about 30 miles into the drive. Then the car started misfiring, and the ses light started flashing at me. Even the y pipe started banging like crazy, I thought it was about to fall off.
I checked the code and it was a P0300 random/multiple cylinder misfire. I also removed the AIR, I am not sure if this has anything do with it. I have no idea if it is burned out o2's, if the car is running too lean, if it is loose plug wires, I just have no idea. Please help.
I checked the code and it was a P0300 random/multiple cylinder misfire. I also removed the AIR, I am not sure if this has anything do with it. I have no idea if it is burned out o2's, if the car is running too lean, if it is loose plug wires, I just have no idea. Please help.
I would check the plug wires. They may have been to close to headers and got burnt up or they could be loose. Could also be a cracked plug but I would think it would have shown up sooner if that was the case.
my first header install my buddy dropped a plug and cracked the porcelain, didn't notice it til we had the car on the road but it did the same thing. a lot of guys do break plugs doing headers, it's common. make sure all the wires are tight too.
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
Originally Posted by lugnutt
Make sure your o2 sensor wires arent hitting the header and shorting out.
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Having the same trouble. Installed LTs car ran rough. checked and replaced all plugs like recommended (found 1 cracked plug and pin came out of coil pack connector) now running worse, huge backfire problem. hope to hear how you solved it or get some help. Just bought a scanner to check codes same P0300. Can you get the coil packs on backwards? 1st col on pass side is labeled 1 or 8 didn't have drivers side off.
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I was able to fix it. It was only a couple of the plug wires that werent attached all the way to the coil. Everything else looked fine. I appreciate all the help.
But now my y pipe is banging like a mad man. I did a quick search on how to fix it but I couldnt find it. I have prothane motor mounts and I planned on doing it with the headers install. But right when I looked at the mounts on the car, I instantly knew it was going to be like a 5 hour job, so I laughed and just kept on going with the headers. Anyway, could someone post a link or just tell me how to do the mod everyone does.
But now my y pipe is banging like a mad man. I did a quick search on how to fix it but I couldnt find it. I have prothane motor mounts and I planned on doing it with the headers install. But right when I looked at the mounts on the car, I instantly knew it was going to be like a 5 hour job, so I laughed and just kept on going with the headers. Anyway, could someone post a link or just tell me how to do the mod everyone does.
not sure but I think some guys had good luck changing the driver's side mount to prothane? Anyways a quick and cheap fix is using a mufflex bump stop. A bracket clamps onto the exhaust and has two rubber hangers that goes to another bracket you bolt to the car. Just put it together, turn the clamp on the pipes til it pushes the pipes down from the car some and it's good to go. I modified the bracket to bolt to the tunnel brace bolts and it worked great!!
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Joined: Jul 2006
Posts: 1,179
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From: North Bay, Ontario
i had the same trouble with my car...ran fine at first then a few miles later would barely run. Ended up being the 2 front o2 sensors. Replaced em with BOSCH 13111 and have been great, no problems and no need for extension. As for the Y banging the floorboard, i just fixed that problem today with poly motor mounts. My exhaust at one point was tucked up only 1/4 inch from the floorboard and it doesnt move at all now! Make sure all plugs and wires are tight and change the 02's! Good luck
Well, my car is seems to be falling apart now. My miss fire came back, and I broke a header bolt. I heard a small exhaust leak from the flange, went to tighten it up, and found the header bolt head barely hanging on. Talk about being pissed. Can anyone tell me how to fix this without pulling the motor. Also, is it safe to be driving around like that, as in will I blow the gasket?
Also, I just finished changing the plugs and found that the plugs on the drivers side were in decent shape, but the passenger side plugs were completely covered in carbon. I thought that was a tad weird. Anyway, it was running fine for a couple of miles, then started shaking on me again, and of course the ses light was flashing at me. I triple checked the plug wires and I am 96% sure it is not that. Does this mean it is the o2 sensors? I really need this car to be running by tonight. Thanks.
Also, I just finished changing the plugs and found that the plugs on the drivers side were in decent shape, but the passenger side plugs were completely covered in carbon. I thought that was a tad weird. Anyway, it was running fine for a couple of miles, then started shaking on me again, and of course the ses light was flashing at me. I triple checked the plug wires and I am 96% sure it is not that. Does this mean it is the o2 sensors? I really need this car to be running by tonight. Thanks.
I went ahead and bought some new o2 sensors and the fixed the problem right away. But there is still the problem of the broken header bolt in the head. I will see how much I am going to get raped on that.
