ssean92

my lt1 seems like it has a miss it when it is cold. but if i get in it, it clears up. once it warms up it seems to go away. i think it might be the gas but not sure. it just dont feel right. any idea's, and one other thing it seems to stumble then take off once i get in it. i have cked the plugs they seem to be good, cked plug wires, adjustable f/p/r, cant think of anything else it could be. i put some seafoam in it to see it that helps. any ideas would help

Hawk

could be your 02 sensors. When the 02's warm up, the computer goes into closed loop using them. If your car is runing good when it's cold "open loop" I'd check the o2 sensors.

You can do this by unplugging both of them and forcing your car to run open loop all the time, and to see if it runs better.


Brian

HardcoreRM125

No he said the opposite I think. It misses when its cold, but if he gets on the throttle it clears up.

Once it is warm, its OK.

It is possible that you got a load of bad fuel. Keep us updated if it gets worse. And run that tank out pretty good ( 1/8 or less ) before you fill up that way you know that if it keeps doing it, its not the gas.

ssean92

well guys it didnt go away, but i didnt get the tank as empty as i would have liked. i put 11 gallons in on my fill up. well it seemed to not improve at all but seemed to get worse. if i drive it during the day it sems ok but if it sits out side at work overnight it is real bad. look at my sig do you think my tune might be it for what i have for mods? I have a custom tune for wot and pt. but when i ck my pugs they are almost white with a little tan tint, it looks good to me but i wasnt sure if that was to lean. i have replaced the whole ignition system when i put the engine in so i hope it isnt it. I did take the front of the engine off to ck the opti to make sure it wasnt something dumb, and to fix the water pump bearing seal that was leaking oil. well i hope to have it back togeather today and will be driving it again to see what it does. i will let you guys know what happens.

ssean92

well seems like the issues is gone. i cleaned up the opti, put new water pump seal/ bearing seal in, put connector gease in all the conectors. it still had the issue when i went to work last night, but on the way home this morning and got on it and a black cloud of smoke then pow, the issue is gone. lol go figure. must have been that gas that finally got out of the car. just wantet to let you all know\. thanks for all the advice.

ssean92

well it is back, i hope it isnt the opti, i think i am going to clean the mass air, see if that helps

ssean92

well guys it is still there after swaping out the opti again. i checked the o2's and they are good. cked all the plugs and they seem to be good. cked coil,spark plug wires. all good. ok this is what i found with my scaner. the lft bank o2 jumps around from 100-900 mv, the rt bank stays at 800 to 900 mv, i cked all the injectors and they are good. so what do you guys think my problem could be. i swap the o2's from side to side and it didnt change. and i dont have any codes????? and i dont have a ege or air pump and they are deleted out of computer. please help. do you guys think the iac valve cause this?????

HardcoreRM125

That o2 sticking on the right bank means it is running too rich. The higher the voltage, the richer the mixture.

And if the IAC valve was screwing up, I would think that it would only do it at idle. I also, dont see how an IAC valve could be bank-specific if it was ****ed up.

You said switching the 02s around didnt fix it. So you can rule out the actual 02 sensor. I would be tracing the wiring for the o2 harness on that side. Get some scematics and check it out.

You said you checked the injectors and they are all good. How did you check them? Pull the fuel rails off and crank the motor. They each should spray a nice cone of fuel. Not dripping/spitting or anything like that.

Are you sure you dont have an exhaust leak immediatly before or after the 02 sensor?

Maybe one of your injectors is sticking open under WOT.

Try switching 4 injectors from one side, with 4 injectors from the other. See if the problem follows over to the other bank.

Are you SURE you dont have a plug wire, or an injector wire clip on the wrong one? If you have a plug wire mixed, it will misfire badly. Same applies if you switch an injector plug by mistake. And it could read rich from that on that bank if it is giving it fuel too late or something.

Good luck with everything,
Joe

ssean92

well i changed #7 injector swaped from side to side and dropped fuel pressure to 44 and it is smooth again. so i quess it is fixed for know. i am quessing that the fuel pressure fixed it, now that i think about it it started to run crappy after i took the vacum line off the adjustable fuel pressure regulator. but any ways thanks for the idea's and it help out.

HardcoreRM125

Glad to see you got it running right again

ssean92

yeah you and me both. lol will see how long it lasts though. as of late it has been done more then running.

ssean92

hey guys i have another question for ya all, why would my car have a ruff idle and cruise, if i have the fuel pressure above 42psi? if it is at 42 it is fine anything above that is feels rought till i get in it. just curious this ended up being my problem??????? i drove the car for 6 months with it at 50 till now any ideas?

HardcoreRM125

It will make it run too rich. Think of it like running a carbreuted vehicle with choke on the whole time. It's not an efficient burn. It makes it run rough. I bet you were getting ****ty MPG too huh?

ssean92

i quess that makes since. i just didnt understand why it just started. and yes i had been getting a crappy gass mileage, but it was still 17 around town/state route driving. thats with the 6 speed. thanks for all the replys you have helped out alot. i do plan on going to the lt4 cam soon shold i go to 50 once i do that? i plan on getting the tunner cat program once i do so i can do my own tune. well thanks again for you help HardcoreRM125

SMW

My 454SS had similar symptoms. Miss when it was cold, like below 45 degrees and stumble real bad until it warmed up. Checking my O2 counts with an engine analyzer (Autoxray) it turned out it was running lean. I put an adjustable fuel regulator on it and richened the mixture. It's been running great ever since. I'd check your O2 counts.........