Loudmouth LS1

iTrader: (10)

Vacuum Leak or O2 Sensor?! Please help, can't figure out how to fix this thing, there are no codes being thrown except 507 - Idle Speed High which i've had for a really long time, it's really starting to **** me off!!!! Thanks for any help guys!!!!

PS - Had intake off to replace knock sensor about 1 week before problem started, but went to the track that night and it ran great, and then was great for about a week, and then these problems started!!!

PSS - Whatever the problem is, it's causing the car to run totally Pig Rich and majorly fouling up the plugs and causing the car to misfire, they're just caked in Carbon!!!

quickWS6

I had this problem for a long time. Did it happen all at once, or did the Ltrims slowly get out of whack? Any changes right before this happened?

Loudmouth LS1

iTrader: (10)

I don't know, I just tapped it for the first time last night, and it was at 25 and -1.6 right when I started it! No changes to the car except pulling the intake about a week before the problems started to change a bad knock sensor!!! What was the problem with urs, please any info would really help and be greatly appreciated!!!!

KGSloan

i had this excact thing happen and it ended up fouling out the entire passenger side of spark plugs. it turned out that i had blown out an exhaust gasket where my collector bolts to the exhaust. it threw my o2 sensor all out of wack and made the car run really bad (just like you described, fouled plugs, missfires, pig rich). the car started dumping fuel and the ltrims were really messed up. i would check for an exhaust leak somewhere in front of or around the o2 sensor that is messed up. i would bet you that is what the problem is. good luck to you

Loudmouth LS1

iTrader: (10)

Every single plug in the car is fouled up, so i'm not sure that would be the problem, and it also doesn't sound like I have any exhaust leaks, but you never know, but also, I doubt both sides would go bad, right? And thanks for the info, cuz i'll definately check around!

quickWS6

Mine started as a bad coil, and somehow the wiring between the coil and the harness went bad, which caused the plugs on one bank to foul and the 02 to foul out too. Swap the 02 sensors from each side and see what happens. If the Ltrims change banks, then it is the 02. If they don't, then I would either look for a big exhaust leak or a pretty large intake leak. Is the entire bank misfiring, or just certain cylinders?

Loudmouth LS1

iTrader: (10)

All 8 plugs are caked in Carbon! The reason why I checked, was to see if I could figure out which cylinder was missing, so I could replace the wire or coil, or whatever and like diagnose the problem, and it ended up being all of them were fouled, and then that's when I realized something else had to be wrong and I ataped it! It was originally throwing a code for a bad throttle position sensor when this problem first emerged, so I replaced the sensor and figured that would solve the problem, but it didn't, I actually think it's worse now!

GueSS Who

If you have a intake leak it will surely do that. Any unmetered air can cause this. I see this alot of F-bodies. It also will happen if the 02 is seeing oxygen on one side, IE blown gasket.

quickWS6

Use Atap to find out which cylinders are misfiring, that will narrow down the search. I would change all the plugs anyway.

Loudmouth LS1

iTrader: (10)

It shows misses on all cylinders

Loudmouth LS1

iTrader: (10)

That's what I figured, gonna try changing my intake manifold gaskets, they looked kind of cruddy the last time it was off the car.

Reckless

iTrader: (9)

Check your injectors wiring for continuity. I have had several injector wires break internally from doing lots of work on the engine all the time. If one or more injectors is not firing, you will get a misfire and that side will be very lean because air is just getting pumped through with no fuel.

CHRISPY

PCV EGR or vac leak likely. Check coils, wires and plugs as well.

I would lean towards vac leak myself

Reckless

iTrader: (9)

Could be, but I bet he finds a loose wire or bad wire on one of the injectors. How's a beer sound Chris?

Dustin Butts

iTrader: (5)

Definitely back track the intake manifold removal/install. Check all vaccum connection around back. Check all connections to all sensors up top. Look for pinched wires under the edges of the intake. Make sure all injector clips are secure. Look for wires that may have touched headers. Swap O2's as was suggested above. Look for simple stuff first.
Then change intake gaskets and use the proper torque sequence and specs.
Replace plugs. Try it again. It's probably something simple....don't fret.

CHRISPY

I didn't even read your post till now. Yep could be injector wiring too.

With all the plugs caked it sounds like vac leak though Could either or both


Beer sounds good

Pro Stock John

iTrader: (34)

I'm thinking intake manifold not sealed on one side did you use a torque wrench, I am guessing not.

Loudmouth LS1

iTrader: (10)

I actually just fixed the problem yesterday. I didn't even think of it, but one of my friends suggested that since I had a bad Throttle Position Sensor and that caused the plugs to foul out, that it probably fouled out one of the O2 sensors too, b/c I replaced the TPS and figured that would solve the problem, but it didn't, so I took the O2's out yesterday and torched them, and it's been running great since, no misses or idle issues. Thanks for all the help! Hopefully it stays working, if not, then I know it's a vacuum leak somewhere, I haven't gotten a chance to tap it yet, so i'm just goin by how it's driving, so I guess i'll see once I get some more miles on it! Thanks again for all the info!

PCMFORLESS

Glad to here it is running good for you now. I see problems with O2's very often whether they are bad, lazy or the wiring to them is melted, and it really makes the car run poor as the PCM reads them as lean and adds fuel you do not need.

Loudmouth LS1

iTrader: (10)

Thanks! One of the reasons I didn't think it would be a bad O2 is b/c it wasn't throwing a code for it and I assumed it would've! I still find it kind of weird!