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Drove the Spec B up to Lava Hot Springs for the weekend with the girlfriend. She was driving it back home and downshifted to 4th to pass a truck. Around 4500rpm the car bucked and check engine light/traction control light came on, and the I-drive S/cruise started flashing. Car ran fine after that but she was freaking out thinking she broke my car. Drove it down to Evanstan where we switched. Only strange thing I noticed was fuel gauge wasn't working. It was stuck at full even though we went 140miles. Once I took over the car ran fine, but if I went WOT around 4500rpm it would do the same thing, buck once and then keep going. Strange. I'm thinking it is overboosting or FPR. Strange. Car is stage 2 with a cobb protune. I pulled the battery last night to reset the ECU, and it has been fine since. No issues/bucking. I wonder if the colder weather/elevation or something just caused an overboost and it to fuel cut or something.

Any ideas?

You're having some fuel issues it sounds like. Pump might be going, or you have an obstructed line. Because it sounds to me like the fuel system is having trouble at maximum flow. So it could be the fact that the pump is falling flat on its face. Or there could be an obstruction keeping fuel from flowing as efficiently as possible. It could also be a number of different things, but thats where i would start. Oh, and btw, have you checked the gas cap?

I haven't checked the gascap yet. Reset it last night and still working fine. Some reading on LGT.com indicates it was probably just an overboost situation from the elevation chance. We were up in Wyoming/Idaho and when she went by the car it probably just overboosted and threw a code.

I agree the guys running open source from a local guy in ogden have the same exact issue when we run monte and hit the high elevation and causes fuel cut!

It has never been an issue before so I am not sure I should even worry about it. What would the solution even be?

Reset the ECU... Do it the right way though.

Which would be?

Car is running fine all day.

Turn everything off while the auxilary is on (fans, radio, head lights, dome lights, ect), disconnect the battery and depress the brake pedal for 15 seconds. Then reconnect the battery and WITHOUT TOUCHING ANYTHING/ PEDALS, put the key in the ignition and turn it to "on." You should hear a relay click in the dash. At this point in time, you should depress the clutch pedal, AND ONLY THE CLUTCH PEDAL, and start the engine. All of this without touching anything/ turning anything on. Let it idle, without touching anything, until the it reaches operating temperature (once the radiator fans kick on), this allows your ECU to get all up close and personal with the sensors, calculate idle speed, and all that jazz. After all of this, you have successfully reset your ECU the CORRECT way.

I have know idea where you heard that 08whiterex....But it doesn't sound right! I have been to chrysler training and some threw gm at HQ regarding the pcm and flashing and programing. And never once has that ever been said to me. Even by the lead engineers. So I ask who told you this?

Nasioc. Over and over and over again....

EDIT: It makes sense to me. You're just letting the ECU re-learn, and it also makes sense that any outside electrical draw would foul the calculations of idle and the like.

Ok then!

It seemed kind of strenuous to me at first too. But it makes sense to me now. I mean, the ECU does learn, and this gives it a good solid platform to stand on. I mean every time i disconnect my battery, for like the first hour of operation, my idle is all lumpy and uneven. Will idle at normal, than slow to almost stall, than sputter back to life. After i did it this way, no weird uneven idle. IDK, it works for me.

yeah happened to me and it sounds like pretty much the same thing. I just hit fuel cut off because of the high altitude. It has only happened to me once, but it sounds like pretty much the same thing.

You really don't have to go through all that trouble for the ECU to "re-learn." It's good to have it at operating temp when you do the reset, but I wouldn't worry about touching stuff. I usually reset my ECU with LearningView. But, without Learning View it's still pretty simple all you have to do is unplug the battery. Press the brake pedal for 10-15 seconds. Plug the battery back in. Turn ignition to ON. Listen for the relay click. Turn the key to start the engine.

As far as the car relearning. The major aspect (assuming it's a decent tune), is the Ignition Advance Multiplier (IAM). When the engine resets (for 32-bit ECUs) it sets the IAM to .5. Essentially running only 1/2 the timing advance in addition to the base timing map (in all honestly, not really a huge deal, it will go back to 1.0 on it's own given some gentle driving).

To get this back up to 1 IAM quickly however (where it should be if the tune/gas/car setup is decent, and no feedback knock correction is detected). Cruise down a road, hold the RPM at 3000-3500 rpm, and lightly apply the brake and gas simultaneously so that you can maintain that RPM. It should only take ~5-10 seconds and the car will bump the IAM back up to 1.0. It's pretty imperceptible to the driver when this occurs unfortunately. With a week of gentle driving around town your car should bump up the IAM, relearn the MAF scaling, fine learned knock correction and all the other learned goodness.

The only way you could hurt your car by driving around with a newly reset ECU (that I can think of) is if the tune/gas is bad and it no longer has the fine learned knock correction tables. OR you have some intake mod, and the ECU tried to compensate the MAF scaling in the learned tables. Do I think you should reset your ECU and then drive around WOT? No. When I usually reset my ECU with a new map, I do a fair amount of logging to make sure all is kosher.

If you have a spare $200 for a tactrix cable, or a b-day coming up. Get it. Just being able to log, and see what the deuce your car is thinking is a HUGE help. At least for peace of mind/keeping your sanity.

Pretty rough crash course... there's a lot more reading (and better/more accurately written) at romraider's website.

And... i'm rambling again. Someone should really put a time limit on these quick posts so I don't do this. Dammit.

WHere can you pick up one of those tactrix cables? I want one just for the logging and what not..