Bought a OBD2 to check it out, all i got was errors for not having the Secondary O2 sensors in but im pretty sure thats not causing this issue. I couldnt find any leaks and it is not showing up as a code, should i clean out my throttle body?? even if it doesnt show up as a code. its a minor lump in the idle and it only happens in park and neutral. Car runs real good.

 

Gonna go plugs on this... how long since you swapped?

 

put in brand new NGK one step colder plugs, car was fine till I did the spark plugs and went catless it was done in one shot. The tune didn't knock it out. I'm assuming it's maybe the throttle body needing to be cleaned. But I didn't have this problem till I brought it to do do this work.

 

Is there a reason you're running one step colder? Try swapping back to stock plugs and see what happens.

 

By lump do you mean like a slight misfire at idle?
How many miles on your car?
What mods etc?

 

If the car has one step colder plugs and headers then you could a expect a slight Little Rock type feel that Avery minor when parked as long as you got no codes miss fored and runs strong your good to go

 

Yes exactly how u explain it, thank you.

 

I even googled it to find out what you mean but I don't get it... little rock feel??

 

A intermittent ever so slight shudder of mine is anything to go off. By intermittent I mean its smooth, shudders slightly back to smooth then small shudder. I guess? Description words lol

 

Yeah that makes sense. Mine shakes consistently like a muscle car (which it is a muscle car really lol)

 

It's bc of the headers I'm pretty sure but the spark plugs too, I have no CEL for misfire so It's just a normal hiccup I'm assuming. My car idle fine and when I did the spark plugs and catless headers(one shot) it gave me the slightly rough idle. I would've cleaned my throttle body and MAF sensor but if it was good before this why would I. So I'm gonna go with tuning to ease the hiccup but the car drives 100% normal no hiccup it's the idle in park

 

Yes,very normal after headers more some L.T it's just getting so much more flow now.

 

Normal with the headers as mentioned dozen times.This the joys of modding your car,it won't feel and be like stock anymore.The colder plugs,will attribute to this too ..

 

lol im gonna slap the 77 and the injectors and fuel rail lmfao hiccups are only gonna get worse

 

Just wanted to comment I have a similar rough idle after going to Eurocharged headers. I can't tell its rough until I turn the stereo off and really feel for it. I eliminated my primary cats while doing the headers.
No CEL for misfire.

In chasing this rough idle condition down I replaced the following with no change:
Lemforder motor mounts x2
Lemforder transmission mount
Bosch Sparkplugs FR6MPP332
Valve cover gaskets - checked crank breathers for poor connections
Confirmed okay plug wire resistance

Had I not found this thread I would be taking a good hard look at my coil packs but the car pulls hard.
I will probably replace the pulley and tune once the weather warms up.

 

 

What happens is the engine breath harder making the light shake at times.

Also ,carbon build up and dirty fuel system can do this too.

\Some m113k setups just idle this way ,as long as it's not ruff in drive it's fine.If you want silky smooth idles stick with a Honda or so..