SuperSlow420

Ours cars sputter and shift hard when you shift in mid to high boost pressure silly! Most Sticks ive driven in 5th gear at 35-45mph tend to make the motor work overtime! It's not highly recomended and will ruin ur motor over time!

Terminator2

Florida is pretty flat, but when I do encounter a hill I downshift to 4th. I try to get the best gas milage posssible out of this car. I almost never apply more than 25-30% throttle in 5th

Psykostevo says that he has seen many LNFs that exibit this trait, and I am willing to bet that it is a calibration issue with the ECMs in a lot of these cars. Today it was much cooler this morning and I did not notice the issue as much.

superbrowndude

iTrader: (2)

Im still a bit confused. My Sig has my mods. In low gear around 2000rpm I have a max knock of 3.6. And a small misfire. So would this be normal with all the power,about 315 whp and 340 wtq. Will this change at all after I do the ttr motor mount?
At higher speeds and rpms theres no knock or miss fire.
What do you all think?

Im still a bit confused. My Sig has my mods. In low gear around 2000rpm I have a max knock of 3.6. And a small misfire. So would this be normal with all the power,about 315 whp and 340 wtq. Will this change at all after I do the ttr motor mount?
At higher speeds and rpms theres no knock or miss fire.
What do you all think?

I don't know if it makes a difference but my A/F 's around normally around 14.4-15. Do you think its to rich with vinces tune,my fuel trims are also wacked and all over the place.

cmiller8006

iTrader: (3)

Talk about an old thread. But this is what is going on with my car right now. However I have it back to stock and it is still doing it. I have a interceptor and it is recording missfires on all cylinders. And its only at the about 2000rpm range in any gear.

RYRO14

iTrader: (1)

Yeah my car does the samething, I dont know what it is. Talk about an old thread I thought it was new and was like WTF Terminator is asking us how to solve his misfires lol.

army_greywolf

iTrader: (2)

So i've been tracking this issue. I even went so far as to do a datalog of it. While the software reports no knocking it reported 17 multiple misfires that I can see but wasn't throwing a CEL . I did my best to compensate for what I believed to be MAF sensor turbulance with tuning. I should have messed with AFR but I am not well enough with tuning these cars to **** with much yet. Although this time I had only a couple misfires reported. I really got to wondering about it so I took my plugs out and checked the gap (which is factory set at .036 straight form a brand new crate engine). I regapped them for .032, where I then made note I had a single misfire event, once again I gapped them for .030 and now I report no misfire events at all. Driving it seems smoother. Is there an issue with the ignition system or something I can program in that area for whatever reason I am not aware of? I know in some computers I can program for multiple spark events in one cycle.

cmiller8006

iTrader: (3)

I believe it is the purge valve thingy. BYT had me unplug it so it wasnt working, it threw a cel but it quit doing it. I also observed that the afr's would jump to about 17-18:1 and quickly go back to normal. My buddie who is a gm tech said that when the valve opens it is like a metered air leak and it is not compensating for it like it should and is causing it to go lean and the missfires.

Terminator2

I think my valves were sticking a little when the car was new. I no longer have that issue even lugging the car around in 5th at 40-45 mph (Gets 50 MPG and I do it only on flat ground, not many hills in Florida)

SSlobalt

Funny to see how much Term has learned in two years.

RoadconeTuning

Mine does it all the timr around 1700rpm... if you are at just the right load in 2nd gear it'll buck so hard its like the car cut off ans the started itself again....

Iam Broke

iTrader: (10)

We all have.

HHRSSouth

Same, then I got to where Termi asked Psyko dude to tune his car if he was ever in Florida I immediately looked over at the date and realized it was long before Termi dived deep into tuning with HPT

While this is a older post, Kudos to the guy who searched, found the thread and bumped it looking for an answer.

efactor

iTrader: (2)

does it sound like your car wanted to kill itself (shutdown), backfiring, and misfiring? just wonder if that was kind of related to my experience. my car has been normal for a week and a half.

superbrowndude

iTrader: (2)

So this means what for lil old me ?

Reecebove2250

I have a 2010 cobalt 2.2 that’s an auto and it does the same thing my autotech teacher told me to try buy new coils and i just spent $168 for nothing basically

ECaulk

iTrader: (6)

Well the 2.2 is not an LNF code engine, it's a LAP.

It's possible you have other issues, it could be the start of a failing MAF (don't just throw parts at it, test them), it could be issues with the transmission, and the list goes on and on.

USMCFieldMP

iTrader: (1)

Something that you'd think an autotech teacher would teach them... I thought that was the point.

ECaulk

iTrader: (6)

Sadly with some teachers, they believe they have the answers to everything upon hearing part of the issue or situation.