m2g4b

iTrader: (8)

okay im still new to the LS1 car, and i have been doing major searches on here for about 3 weeks, but just cant quite pin point my problem so here it goes....start the car when its completely cold, engine temp wise....it will start up and idle then it will start slowly idling lower and lower until it about dies then rev itself back up to around 1500 and then come back to normal....sometimes thats it sometimes it does that about 2-3 times then dies. if it dies it wont restart without putting the pedal to the floor and then it will run rough and blow tons of black smoke out the back then it will straighten up. another thing is if it starts and i take off before it totally warms up it will bog really bad and start to buck in first and 2nd, just like its being choked to death. im at a total loss here, i have been told its the tune, its the plugs and wires, its the o2 sensors not being hot enough???? its a 2002 car, engine is presine condition as far as rubber hoses and such, it does have long tube headers, ory pipe, NO CATS, air pump deleted from the car....any help would be greatly appreciated, it sucks no knowing when and if the car is going to run right everyday!!! thanks in advance!!!

DWZ28

Id say first check plugs and wires if theyre good double check your sensors on your lid
Mabe your MAF sensor isnt working?
What octane gas do you use?
I had a simular problem when someone bought me a tank of gas and put 87 in it, ran horrible for about 500 miles.

m2g4b

iTrader: (8)

wire "look" good, they are some cheaper auto zone wires that came on the car, dont know bout the plugs at this point.....i use 91 or better in the car, all the time!!!!

94Firehawk161

iTrader: (7)

Do you have access to a scanner so that you can view data? Has the car ever been tunned? If so, it may have a "corrupt" tune. If you know someone who can put a stock flash back in it, you may want to try it, but I would look at the data from a scanner first to be sure there is no other problems.

miamifan3413

iTrader: (1)

It could be alot of things.....you need to get it to a shop and get it scanned.

m2g4b

iTrader: (8)

when you guys say scanned, are you meaning just a diagnostic scanner or even autozone, or to a tuner person that has that kind of software? it is throwing zero codes. i had a tuner guy turn my rear o2 sensors off and redo the speedo with the 4:10 gears. he said it looked like someone was in the program before, but didnt look out of whack or anything...

ping2day

iTrader: (5)

I had a similar problem. My plugs were toast due to the o2 sensors asking for fuel. Tune them out, or go to open loop.

m2g4b

iTrader: (8)

ping- you can tune the front o2's out completely? and or make it stay in open loop?

DirtyJohn

iTrader: (8)

If it was running before with those mods and now isn't running and nothing hardware or software has changed it would have to be a mechanical or electrical (sensor) failure.

You can get a list of codes to see if its the latter from Autozone, write em down and look em up or bring em back here to see whatsup.

I'm guessing something is loose since you say your not throwing codes.
I had intake leaks and the car ran like complete poo but had no SES or codes to speak of.
It was also running rich as hell.

m2g4b

iTrader: (8)

bought the car with the mods already on it, checked the intake bolts already, also had the car running and sprayed wd all around to see if something might show up...had the car dyno'd just last week and yes it was running a tad rich but the guy said that was just from the headers!!! it seems like it only does it on warm up.....then it is fine????

ping2day

iTrader: (5)

Like i said i had a similar problem. I believe my tuner had my front O2 sensors tuned out. One of the rear sims may have been bad causeing massive amounts of fuel to dump and wasted new plugs. He put the car in open loop and and new it is fine. You may have to put it back if you wish to pass an emissions test. Some pass and some don't in open loop i understand.

m2g4b

iTrader: (8)

I will check into that then, i have no emission test to worry about here in oklahoma so no concern there.....i dont have any rear o2's even on the car at all, no cats...just the front sensors are there...

DirtyJohn

iTrader: (8)

I dunno, if it were me I'd check to see if everything that touches air before the motor is tight FOR SURE...
MAP, IAT, IAC, MAF....you get the idea. (although if you say its all good then I assume it is)

Then id prob check TPS is within range.
If that's fine I'd potentially pull the MAF connector.

But I haven't had to troubleshoot much with these motors, and I'm a big fan of taking stuff apart and starting from scratch.

chase3

iTrader: (1)

mine did the same thing...it was an intake leak..i have the air pump removed and the plug in the top of the intake was loose and it had the same effects as what you described..on the scanner it will read fuel trim problem...thats my guess