Power Loss (feels like fuel cut)

So I headed up to Cayuga Raceway today to get some road-racing in (about a 2hr drive from Buffalo where I was staying --I live an additional hour away from Buffalo in Rochester).

Trip up there was uneventful, car ran well. First lap out on the course was good, second lap, I noticed what felt like fuel cut in 3rd gear at higher (5k) rpms. I let off the gas and then got back on it and it was fine. I go around the track again and it starts happening again on the straightaway, so I shift into 4th and it seems ok again.

I get to the back stretch and am in 3rd gear and it started happening again so much so that I couldn't accelerate at all. I dropped down into second and the car would barely move; felt like a limp mode... check engine light also came on. I pulled back in the pits and turned the car off.

I checked vaccum lines and intercooler fittings and all were snug. Since I was so far from home, I didn't want to screw around with things too much, and on a suggestion, I reset the ecu via a battery disconnect. That seemed to fix it, but I unfortunately didn't get a chance to check the CEL. I had this happen in the past at Watkins Glen, also in a road racing situation... but it never tripped a CEL and went away on it's own quickly.

Has anyone experienced anything like this? Car has no engine modifications, only suspension and only has 8k miles. I'd take it to the dealer, but the problem's not there now and if they can't reproduce it, then there's no problem in their eyes.

Help?

Cliff notes: On road course, car loses power at higher and eventually lower rpms. Pressing accelerator doesn't move car and car seems to be in limp mode. CEL is triggered, but I couldn't read it (nothing to read with).

Disconnecting battery 'fixed' problem.

Yep, that was intact.

Car ran like normal after the battery disconnect so I'm thinking it's more of an electrical issue than mechanical

These are the only similar occurances of this problem that I can find (similar, but not the same... the cruise control or other lights weren't on):

http://www.legacygt.com/forums/showthread.php?t=23683&highlight=fuel+cut

http://www.legacygt.com/forums/showthread.php?t=22785&highlight=fuel+cut

bump... anyone have a similar problem?

I don't want to take the car to the dealer and have them try to reproduce it as it's just an excuse for them to beat on the car (which should be reserved for me!)

Hi Scott, sorry your track day was cut short

Try to replicate it and get the CEL to come up again, then get it read, should point you in the right direction.

I acctually had a similar issue about a couple of weeks ago. I had a lil diff sircumstances though. First off it was pouring and I have an AEM Cold Air intake. I was leavin the toll booth and wanted to smoke my buddy and as soon as I asked for some boost it seemed to cut fuel and buck and then check engine light came on. Once that was on it wouldn't take more than about 3 or 4 pounds of boost(guesstimate, because I have no gauge.) It would just fuel cut and fall on it's face.

However with a battery reset she was good to go again until I really wanted the high end pull again.

So using my brain I stopped beating on it the rest of the day.

After the rain went away(ever since) she runs perfect.

I just chaulked it up as breif water ingestion. I'll have to take it easy in the rain maybe even snow which will definietly get me to sell the AEM.

There doesn't happen to be an air filter box sitting on your TMIC does there? Sounds like it's pulling timing from heatsoak and knocking..

You need to pull the codes, use the dashboard reader.

How much fuel in the car at the time?

Maybe with the high sustained Gs you were experiencing fuel starvation at times and that triggered limp mode?

I've been trying to reproduce it, but it's only happened on track conditions and I don't want a speeding ticket :-) I need to pickup an odb II cable and do some logging; unfortunately circumstances prevented that this past weekend.

What Keredstg described sounds like exactly what happened to my car. I don't have a CIA though, nor was there anything above the intercooler that would have blocked airflow. The tank was about 3/4 full at the time, so there was plenty of fuel; it also was happening on the straights, so unless the fuel moved to the back of the tank on acceleration, that's probably not the issue (good thought though).

The thought about an injector is interesting though... maybe I'll datalog IDC and see if something odd pops up.

Heatsoak is also a possibility, though I'd be odd that it happened so soon after getting on the track. The temp was in the 70's and the car had sat for about an hour after getting there before going onto the track. Would the ecu put the car into a limp mode if the timing was really pulled?

I also had plenty of fuel at the time.

Was there any rain RochNY91TSI?

Nope, no rain.

I've since gotten a logging cable, but it hasn't happened again --though I haven't been to a track again either

I also experienced a similar situation while on the dragon earlier this year.

It only happened when I was pushing the car really hard and only after I had been driving it for a while (> 10 minutes).

I would get what seemed like fuel cut around 4500-5000 RPM, the car would buck once or twice, and then continue on to redline.

I too am unable to reproduce this under "normal" driving conditions.

Something very similar happened to me today. At full throttle, in 2nd gear (5EAT in full automatic mode), at around 4000 rpm the car just completely stopped accelerating. I thought the car had went dead, but I left off the gas, checked that rpm's weren't at zero, and drove like a normal driver after that. It hasn't happened before (only had it 2 weeks). I didn't floor it the rest of the drive home.

Anyway.... the car was up to temperature (halfway through my evening commute) and it had been raining earlier. The roads were barely wet though, dry where most peoples tires go.

My car is a mechanically stock 05 5EAT with about 10,500 miles. I was running 93 octane (cheap 93 octane) on a Cobb stage 1 93 octane v1.15 tune. My tank was almost completely full, no lower than 7/8 for sure.

I may start buying Shell 93 octane fuel. My stock 03 WRX hesitated on anything other than Shell 93 octane.

Something very similar happened to me today. At full throttle, in 2nd gear (5EAT in full automatic mode), at around 4000 rpm the car just completely stopped accelerating. I thought the car had went dead, but I left off the gas, checked that rpm's weren't at zero, and drove like a normal driver after that. It hasn't happened before (only had it 2 weeks). I didn't floor it the rest of the drive home.

 

Anyway.... the car was up to temperature (halfway through my evening commute) and it had been raining earlier. The roads were barely wet though, dry where most peoples tires go.

 

My car is a mechanically stock 05 5EAT with about 10,500 miles. I was running 93 octane (cheap 93 octane) on a Cobb stage 1 93 octane v1.15 tune. My tank was almost completely full, no lower than 7/8 for sure.

 

I may start buying Shell 93 octane fuel. My stock 03 WRX hesitated on anything other than Shell 93 octane.

It happends some time to all of us:(

Try Shell or Chevron, it's all I have used in the car

It happened to me again this morning when pulling away from a stop sign and punched it so that a car coming over a hill didn't have to slam on his brakes. I'm such a considerate driver.

This time, I noticed FOR SURE that it happened just as the transmission had banged into second gear (full automatic mode again). It pulled hard (like normal) for a split second, then BAM, fuel cut. I left my foot on the gas this time and nothing happened until I let off of the gas, then re-applied the throttle (maybe 30% throttle). I have a full tank of cheap 93 to burn out before I try some good Shell 93 gas.

I was just sharing some more info. Hopefully the gas will fix it. If not, I'll load a 91 octane tune and keep using 93. We'll see. I may need to order me one of those OBD to serial or usb cables and do some logging. I have already installed that TARI software onto my laptop.

Well there may be one common demoninator here then; I had filled up at a gas station that I'm not familiar with. Maybe it's not as frequently used as I had thought (debris) or not to the octane that I had been using.

Maybe I'll try a different station on my next fillup to see if I can reproduce it with other gas (Sunoco is my typical station)

How soon after filling up does this hesitation occur? And how low on gas was the car before filling up?

My car had a little over 1/4 tank before I filled it up. I only got gas so I could put on my new wiper blade without getting soaked, plus gas was so cheap at that station. There is a separate nozzle and hose for the 93 octane fuel. The 91, 89, and 87 octane choices are all on a second hose. I wonder if there was just a lower grade of fuel in the 93 octane tank.

I didn't give my car full throttle until later on that day, but my gas tank level at the time it first occurred was even with the "full" tickmark.

I haven't changed anything besides gas to have caused it. I drive the same most days, mostly calm driving with the occasional full throttle squirt. Tonight I went and loaded 91 octane stage 1 v1.15 maps, just to be cautious until I burn up all of my crappy gas.

I guess it wasn't bad gas after all. I got my car to do it again today. I suppose I could take it in for service, but I'll have to make sure I can replicate the problem easily. I'm sure I won't get much time for a demo ride, if any. So, I'll have to learn EXACTLY how to duplicate it.

I think it happens when I take off normally, then punch it when I'm doing about 15 or 20 mph. It's always been in regular automatic mode when this has happened. Tomorrow I'll get a good handle on it.