5.3-on-steroids

iTrader: (3)

Ok, so I have a 05' 5.3 with a cam headers, and LS6 intake in my 95' S10 pickup. All the wiring was done by jared at CPW. It's been having a problem where when you first start it runs absolutely perfect and strong, but as you drive it and let it get up to temp it runs worse and worse, the truck starts sputtering and missing till it finally shuts off, then you can start it right back up and it will run for another minute or so till it does it again. I pulled all the plugs and all 4 on the passenger side cylinder bank were fouled out bad and the other side wasnt. you can stand behind the truck and feel different pressures and exhaust temps in each of the duals. I've been through 2 sets of brand new o2 sesnors so i dont think thats the problem. Im pretty sure the IAC motor is bad but I got a new one on the way, there are no vaccum leaks anywhere. Anyone know what it could be? -thanks

XtraCajunSS

iTrader: (2)

Are you sure there are no vaccuum or exhaust leaks? This sounds like a classic case. Are you running O2 extensions? It sounds like the truck starts running bad AFTER going into close loop which means the O2's on one side are sending faulty info to the PCM. Otherwise is it possible you have different injectors on one side? The IAC will not cause this kind of problem. It could be a problem in the harness as well.

I would VERIFY the absence of a leak before proceeding.

Thanks,
Shane

Braunbeck

iTrader: (4)

I had bank issues when my O2 went bad, it was the same thing you described only it wouldn't shut off. It would warm up fine drive fine throw a check engine, I thought it was a vacuum leak at the EGR plug in the manifold since the idle would jump when the CEL came on and would continue to keep the revs up until it was reset. I chased it down to passenger side bank and the passenger side O2, I replaced both just because i was under there.

Good luck

5.3-on-steroids

iTrader: (3)

Yes I fixed all the exhaust leaks at the header flanges recently and put on my 2nd pair of new o2 sensors thinking that would fx it but it made no difference. No o2 extensions either. The set of injectors I boughy were supposedly all rated at 28.8 lbs and were all mismatched in pakaging so I doubt they are different. the reason i say IAC is because when I hooked it to the OBD 2 scanner it said it was bad and keeps throwing codes like crazy, plus it idles irratcally sometimes. I will continue to check for leaks. Could it be that my MAF is mounted too close to the TB?

XtraCajunSS

iTrader: (2)

I doubt that. It could be torn or incorrect size injector o-rings on one side though or something keeping one side of the manifold from seating.

Have you scanned your O2 millivolts to see if they are both switching properly?

5.3-on-steroids

iTrader: (3)

No, but it sounds like something I should try. Would any old multimeter work for that? What should the millivolts read at?

XtraCajunSS

iTrader: (2)

They should switch between ~100 to ~8-900. It varies with A/F ratio. The importatnt thing is that both sides are reading the same thing.

Shane

phoenix1987

iTrader: (3)

Are the coil packs wired right? I installed my coil pack harness backwards when I first built my ls1.

Black Sunshine/ 00SS

iTrader: (1)

Could be just one coil on that one side, simple way to check, just unbolt the 4 and switch to the other side & see if you get a miss on that side.

camaroIroc

iTrader: (1)

I have the same exact problem!

5.3, cam, headers..tuned. runs fine for acouple minutes til' warm, then sputter, miss and stalling. i pulled my whole trans out with converter and sent it to a trans shop, thinking i had a lockup problem, currently right now, it is there...and has been there for a week. they say the trans is fine.....

could my problem solely be o2 sensors? my idle is high, because i raised the idle screw..to keep it running, probly a new IAC will fix my idle.

chevysten

iTrader: (5)

Just curious,but why would you pull your tranny first before checking a few other things?

novaflash2002

iTrader: (51)

i assume you have not cats (not the pet) on this vehical? if you do one could be plugged. a simpe way to check the o2 senser would be to swap sides (move passenger sides to drivers side visvesra). if it still continues check for a hair line fracture in spark plugs, try switching plug wires to the oppisite sides, even coil packs.

BAD2000TA

iTrader: (6)

This was the problem with mine - plugged cat. Check it.

5.3LJimmy

iTrader: (10)

If you have access to a scanner you can use that to check O2 sensor activity. It is definitely something that only occurs after it goes into closed loop. What type of O2 sensors are you using?

camaroIroc

iTrader: (1)

my trans was a rebuilt one, with a high stall converter. im still getting all my wiring finished up and did not have the DLC connector yet, i have it now and am in the process of wiring it into the datastream. I had asked about my issue on a trans section and i got alot of advice pointing in the direction of my tcc valve and or lockup mech. it was also an easy drop out.

camaroIroc

iTrader: (1)

i have no cats, and my rear o2's are deleted with my tune. i will swap sides with the sensors, and check my plugs again...then possibly the packs and wires. but first, finish the wiring on my DLC and pull some codes.

Chris10an

iTrader: (1)

Here are a couple of things to check first. 1. Check to see if the right wiring on the O sensors are switched. left wiring mounted on right O2 sensor.This will course the engine to run ok in open loop, when it hits thermostat temp and try to go over to closed loop, it will smell fuel, smoke in the exhaust, gun shot exhaust etc etc. Remember left fuel bank is linked to left exhaust and O2's. 2. switch the right injectors over to the left bank, and start. 3 check the fuel rails, to see if there is something that blocks the fuel flow. Take out all eight injectors, try to set the ignition to run, without to crank the engine. See if all eight pump fuel. Remember to put a plastic box or something to collect the fuel, and don't smoke....