Installed a pair of hooker shorties last weekend, man that was tight

The problem is that it misfires under load...I checked the plug wires for burnt ones but they were all fine, and i tried to push and wiggle the plug boots some and went for another drive and it worked fine for a while then started to misfire under load again..not so much but noticable.

It doesn't misfire when giving some revs with no gear....it's just under load...I had to tighten one of the wires to the block (no 3 from the front on the pass. side) to keep it away from the header...i figured that it might cause the boot to be slightly moved or misfitted on the plug?


Any input on the matter would be appreciated.

Thnx.

 

Ok, I'll guess I've got to figure it out myself....retighten the headers again and check for burned wires and loose plug boots and so on....it's just under load, and especially on low rpm on high gear, this happens so likely there's something loose or something that vibrates somewhere that makes the misfire happen....

 

man, i just installed the same headers this past weekend and everything is working well so far.. i really dont know what to tell ya there man. was it doing that before the install? could it be your valvetrain not adjusted properly maybe? is the idle rough or normal?

 

ONELOUDKAR:

It was not acting like this before I installed the shorties, so I believe it has to be something with the headers or the install, I was really careful with the 02 sensors, so I dont' think they are wasted, I didn't delete the air or the egr either, those are all connected too......
I checked the plug boots on my lunch break today and they seem fine...maybe I should take away the heat shields on the plug boots? Did you leave yours on?

Can you brake a plug wire? I mean the wire itself, if it's bent real bad?
Could a bad spark plug cause this?

Engine runs fine on idle and when I rev it with no gear (no load), but it feels like it misfires, like one plug is gone when I drive it, especially on low rpm:s...but also some at high rpm:s...

I don't think the valvetrain should be misaligned due to installing a set of headers....

 

Mine did this after my header install, it wasn't your exact symptoms but it was close. It turned out to be a burned plug wire. Did you replace your plugs and wires when you did your headers?? If not you probably need to do so. I'm not familiar with the hooker shortys, if they have any plug clearance issues or anything. I ended up burning a wire, getting it replaced, and wrapping the boot on the wire with muffler repair tape(ghetto) to shield away some heat. It has worked like a charm. If you have about $60-$70 you can take it to the GM dealer and they will put it on an ignition diagnosis machine and tell you exactly what's wrong with it. That's kinda steep though. Maybe a last resort if you get frustrated troubleshooting.

John

 

the o2 sensors, did you touch the tips at all? well, even if you did, i dont think that could be the problem. i think it would throw a SES light though.... my shields on my boots are still there. i got the G2 wires from lg motorsports on mine. they are very nice.... im not sure if you can break a plug wire... are you
sure all plugs are sparking? did you change them with the install of the headers? are they all gapped right? i think it is .050 or .50


hope this helps maybe



-Mike

 

Thanks for the tips....
No ses lights so far....I didn't change the plugs or the wires because I was cind of eager to put the headers on when I got them so.. probably should have though ...the plug access got better on the driver side but not on the passenger side...

I think I'll start with changing the plugs and see if it gets any better and if not I'll check the plug wires and replace them...or get it diagnosed like FastZinTennessee said....

thnx again.

 

If you have the wire tied to the block it's probably arching out to the block causing the miss fire. I would route the wire a different way or get some heat protection ie boots

 

Chris'SS:
to be a little more precise..it's not really tied up against the block, its more like tied to the other plug wire that runs further back...

The more I think about this the more confused I get.

Last summer I noticed that the car didn't run any good and I located a spark plug boot that was completely off the spark plug...The thing is that that didn't at all feel as bad as it does now....then it was just like the car didn't feel to run very well...Now it cind of bogs down on low rpm...almost as if every plug boot fell of for .1 second or something...ie it doesn't feel like just one plug or boot is busted...

 

Either a loose spark plug or a plug wire, maybe even the coil wire. Check at night for sparks. Listen for it to arch.

 

if you moved the plug wires some and the problem went away for a while, I'll bet you got a bad wire somewhere. Replace them all!

 

As someone else said, I would 1st replace all the plug wires/plugs and see what happens. If it still is missing then I would scan the car and see which cylinder is missing and go from there.

My guess is your opti could be going out. How many miles on the opti?

 

Did you have the plugs out while you put the headers in? If not you may have broken one.
The only plug wire I had take extra pains with was #6. I put the longest wire on it so I could go past the plug and then back up to it so the wire stayed far enough from the pipe. If you decide to replace wires, you may want to do that.

 

Thought I would share the outcome on the matter. Well I changed the plugs and now it runs fine again
The only fault I could see right away was that on one plug the little metal thing on top of the plug, which makes the connection to the plug boot, was a little backed out on its thread, that might have caused the problem on low rpm when it chakes a bit....
Nevertheless it could be something else wrong with any of the other plugs as well that I couldn't spot right away...

 

good to hear it's running good now!