JBIRD02

iTrader: (4)

I installed my LT's and ORY in April, and my car ran great! a few weeks later I descreened my MAF (cause everyone I know without a screen has no problems). It ran bad for 2 days, then cleared up and ran great until last month. When I start it up, it idles ok at first, then gets worse for a minute or 2, then, like someone snaps their fingers, the car runs great. if I try to drive it before it clears up, it will missfire badly (i have the random missfire code). heres what I've tried so far:
putting the screen back in
changed my o2's
new fuel filter
cleaned tb (especially the IAC)
the problem went away after all of that, but only for 2 weeks, and now its back
PLEASE HELP!!!!!

JBIRD02

iTrader: (4)

I just asked my friend about the problem, and he said to start the car, then unhook the MAF sensor, so I did, and no change, it ran like it always does. He said it shouldve made the car run really shitty, if not, I need to replace my MAF, is this true???

wrencher

iTrader: (2)

Well a misfire is a misfire did you look into that? Recheck you wires & plugs?
Seen it to many times B-4 even a bad or cracked plug

GuitsBoy

iTrader: (4)

Wrencher is correct about plugs and wires. are you setting any codes? SES light on?

Also, your friend is partially right about unplugging the MAF making your car run like ****. Try warming the car up fully before unplugging the MAF. That way the car is running in "closed loop" mode, where it is reading data from your o2 and maf sensors, and not just working off VE tables.

jimmyblue

iTrader: (11)

I think once it gets hot enough for closed loop the
trims are making the mixture all better, but it's
whacked by nature.

Try cleaning your MAF, the K&N may have spooged
up the sense wires?

JBIRD02

iTrader: (4)

thanks guys, this problem comes and goes, making me think its a sensor problem, but I checked my plugs and wires (which are brand new) and everything's still tight. I shouldve clarified that my missfire is only if i drive it right after startup, once the A.I.R. turns off and goes into closed loop, it runs perfectly (no missfires at any rpm, even during WOT). jimmyblue, I will try cleaning the MAF, what do I use??

p.s. it was idling at 1500 the other day, could it be a bad IAC??

jimmyblue

iTrader: (11)

High idle can be a vacuum leak too, which would further
aggravate lean conditions.

Use something like CRC QD contact cleaner that you can
get at home depot, or something else that claims to be
plastic-safe and leave no residue.

JBIRD02

iTrader: (4)

actually, its really rich on startup. I know by the smell and my A/F gauge is maxed out to the rich side. It then starts to lean itself out to the stoich range (this is when it runs bad), then closed loop takes over and the lights bounce back and forth like they should and it runs fine. i'll get some of that cleaner though and try to clean the MAF.
Thanks!

JBIRD02

iTrader: (4)

Someone told me today, it could be a bad IAT or IAC, would either of these cause this problem? anyone have one of these go bad??

ThackerSS

Typically when a sensor goes bad it starts throwing codes left and right.

JoeDirt

I have similar issues since cam/ headers / injector swap.

Sometimes at idle it will jump up to 1200 rpm and hang there and then settle back down after a bit.

Runs like a bag on startup sometimes until it gets warm.

JBIRD02

iTrader: (4)

thanks guys, the only code thrown is for the AIR not being hooked up. As of right now, the problem cleared itself up and is running fine, but I'm sure it will come back soon, this is the 3rd time. If anyone else wants to add their $.02, I would appreciate it!

glennhl

My idle was going all over the place until I took out the IAC valve and cleaned it up. It was coverd with gunk and the valve seat in the throttle body was also very dirty.

JBIRD02

iTrader: (4)

yeah, I'm gonna clean the MAF, and while I'm at it, i think I'll give the tb another good cleaning