I just finished puting a 224/228 .578 112 cam, Ls6 Intake and LTs on my friends 99 TA and I am having some difficulties. The car has not been tuned yet but it has a noticlble miss at rpms below 2000 and struggles to idle. When driving above 2000 rpm its seems to smoothen out but when you put the clutch in it dies everytime. I have checked every plug and wire, removed the intake once to make sure it was sealed and everything was plugged in, and it still did the same thing. I have checked over everything to the best of my knolledge and Im stumped at this point. Any suggestions are greatly appreciated. Thank you in advance.

 

It sounds like you need to tune the idle. The cam causes a false lean reading causing the pcm to dump too much fuel. A good place to start is try scaling the VE table x60, 80, and 90% at 1200 rpms and under.

 

You need to start by finding the miss. Have you pulled the wires one by one to identify which cylinder has the miss?

 

I have not tried that yet. Would it be possible that it is missing on random cylinders and not just one? Thank you for the suggestions.

 

You always get some idle and low rpm missfire with a big cam. Nothing can be done about that, other than program the PCM to ignore it.

 

You changed alot of stuff on the car at once. The computer is freaking out. A tune will most likely fix everything.

 

what codes is it throwing? i ran about the same cam with a 111lsa, ls6 intake, and race longtubes no cats and it ran prefectly fine (even with a crap load of codes thrown) until my o2 sensor wire dragged on the ground then it ran like crap. its got to be something like a vacuum leak or something not plugged in all the way, etc.

 

What all areas could i check for a vaccum leak? It sounds like thats what it is but im not sure what else to check......I pulled the intake off once already and to my knolledge everything looked ok but i could be wrong.

 

pcv area

 

tune it

 

quit being cheap. just tune it! that will allivate 1 problem. then go from there.

 

Sounds like a normal cam install to me.

 

How will a tune all of a sudden get rid of a cylinder missfire? I know it willl idle much better and dial in the a/f but i dont see it fixing the missfire....but that will be badass if it does though. I drove my car around a lot before getting a tune and it drove much smoother than my friends is right now. Thank you all for the advice.

 

A good trick for finding vacuum leaks is use a can of lighter fluid and squirt around all suspected areas. If it finds a leak the idle will change immediately.

 

Sounds like your plugs are fouling. Replace sparkplugs with new OEM AC plugs. Then have it tuned.

Cold nitrous sparkplugs, the wrong plug, or old plugs will foul if too rich.

 

i would check the rear brake booster hose to make sure its not kinked and is connected. reach back and make sure the other tube is connected to the back of the intake and the connecter as well. pull the spark plugs and make sure none of them are fauled or the porceline cracked. what springs did he go with? what all was replaced? how long has it been driven since the changes?

 

I had a problem with mine running crazy when my o2 wire shorted out. Caused the engine sensor fuse to blow. Go check that and start the cheap way. If that fuse is blown it is causing your maf to freak out.

 

Turns out all the plugs were fouled.....replaced them all and now it is 100% better. So now the car is goin to TSP for a tune on Tuesday and should be good to go. Thank you all for the help and suggestions.

 

yeah i dont know why people would even bother not changing spark plugs on a header install, its like the best time to do it. glad you figured it out.