necrocannibal

iTrader: (5)

408 Stroker with about 5000-6000 miles on it. Only when the engine is cold it will idle really low, like 600 rpms, and when you give it gas it will sputter and backfire and not have any power hardly. Once the cars reached operating temperature it5 clears up and runs totally fine. I m thinking its an 02 sensor issue but they are fairly new and the last time I had them checked on Autotap they were rading fine. I really have no clue whats causing this. Anyone have any ideas as to what I should look at?? Thanks.

ls1hybrid

wow! a 224 in a 408!

necrocannibal

iTrader: (5)

Thanks for all of the help.

The 224 was in my LS1 which I blew up and built a 408. It has a 236/242 .598/.610 114+4 cam in it if you must know.

Anyway another thing it does is if I sit and idle for a few mintues my SES light starts flashing like its misfiring but its not. As soon as I start to move again it stops.

Ben R

You should take the car to somewhere that can run a diagnostic check for you so you can find out why the SES light is coming on. That will probably lead you to the problem and it's solution.

v8maro

iTrader: (4)

How do you know it's not miss-firing?

Raped-Ape

iTrader: (1)

i had a 98 camaro a couple of years back that had the same problem, ses light flashing . it was misfiring bad. it turned out to be the ignition control module.
-jonny

necrocannibal

iTrader: (5)

How was that diagnosed??


I am assuming its not misfiring because its only does it at idle and doesnt jerk and hesitate like a misfire when I am moving after its warmed up. You cant really tell if it is misfiring at idle I guess with that big of a cam.


EDIT: It also throws codes for insufficient switching on banks 1 and 2. When I had it tuned the tuner told me he was going to lean it out at idle so that it would help it go through emissions so I assumed thats why it throws those. Could it all be related to my issues?

Mike K.

My SES flahsed and I also had some sputtering and backfiring cause of a bad o2 extension wire, I noticed on my scanmaster and o2 guage that it was pegged at .999 mv's and that on the guage it was holding at the max green meanwhile the other o2 sensor was bouncing back and forth like normal. Jacked the car up and inspected everything then I found that I had zip tied one of the o2 extenders to tight and that when the motor or chassis moved that it had actually pulled a couple of the wires out.
I replaced that broken o2 extender and then all was fine.


You got a scanmaster or any kind of diag tool? This can alot of the time point you in the right direction.

HumpinSS

iTrader: (1)

To help with the o2 codes get the Corvette rear sensors. The wires are long enough for you not to have to use the xtensions. And because they are further back in the vette their heating elements get hotter

necrocannibal

iTrader: (5)

Well I replaced both of mine just recently with the Bosch kind. I inspected my 02 exstensions last night and didnt really see anything out of the ordinary even thought the heat sheilding around it in a couple of places was cut from rubbing. I swear I had this exact same problem and replaced my 02s and it went away. Is it possible that these are bad again, seeing how they are the cheaper ones anyway?


I do not have any kind of scan tool but the only codes it showed lat time I had someone check it was insufficient switching banks 1 and 2. Could that coe be caused by what the tuner did or is it related to all of this mess my car is doing?

Dustin Butts

iTrader: (5)

It's very possible that the O2's are bad again. The tuner could have run you too lean and burnt them up. Get that tuning fixed and replace the O2's. Check all your plug wires to make sure they're on good. A loose plug wire will cause a flashing light and crappy performance.

necrocannibal

iTrader: (5)

Ok I went and had it dynoed today, it was already set up for a local racing website to dyno today. It made 454 rwhp and 460 rwtq with stage 2 LS1 heads that are choking it so the motor is running ok. It also made 528 rwhp and 573 rwtq on a 50 shot. I am going to go with it running too lean at idle and messing up my 02 sensor idea. I will replace them and see what happens.

Dustin Butts

iTrader: (5)

Get a good tune on her. You're right in between TEA to the northeast and TR and FM to the south.

necrocannibal

iTrader: (5)

TEA has already tuned it. It ran great for a few weeks after I had it tuned but slowly started to run worse after the 02 sensor thing started.

Dustin Butts

iTrader: (5)

Got new O2's yet? I sent you a PM. We'll get with Brent and get you fixed up man...don't worry. Still getting a flashing SES? Checked for bent PR's and loose wires and or plugs etc? Vacuum leaks...? pull your plugs and look at them also...

Tiger2o69

iTrader: (16)

Where is tr and fm?


hey redreaper,
That sounds like the same problem i was having except mine doesnt go away when it gets hot it gets worse. What was your a/f ratio? Nice to meet you yesterday and good luck w/ the car.

Oh, i knew something had to be wrong w/ my car dynoing 300 so i went to azone and got my codes pulled and had like 6 different ones . Now i have to figure out what to do. i think its time for a trip to tea or maybe one of thoe other 2 if they are close.

O2bqwik

iTrader: (6)

tr and fms are around baton rouge la

Dustin Butts

iTrader: (5)

Sorry...Thunder Racing and Futral Motorsports