Thread: Car falling out at 50% throttle, scan inside, any ideas??

Alrighty peeps: finished putting in the differential today so I decided I was going to do some tuning.

After my first 75% throttle run, car started actin real funny, here are the symptoms:

1) Anything over 50% throttle car falls right on its face, looses all power
2) A/F gauge goes crazy when car falls on its face, all the "lean" red lights light up
3) car runs fine under 50% throttle, no noticeable differences
4) no odd sounds from drivetrain / engine compartment
5) oil looks good, plugs are all fine.


So...anyone have any ideas??? Here's a scan I did of the car, I held it at the point where it looses power alittle during these scans in hopes I would see something abnormal. You can see where I stop giving more throttle, hold it for a second, then go 0% throttle, this is where the problem is.

Troubleshoot Scan

It seems to me like the car is loosing fuel, or at least thats what it feels like in the car. Stock pump is still in there, how can I test to see if its no good? Anyone have any other ideas? I don't think this could be tranny related, but who the hell knows.

if you're car's loosing fuel pressure u'd be getting tons of KR but i dont even see it when u went up to 70% throttle. thats just something i noticed.

exactly, I dont see any KR, car was at operating temp, but like i said, a/f gauge goes bonkers when this happens as if i am losing fuel, and it does feel like I either have a miss or a fuel problem, no misses though, so i'm leaning towards fuel

How are your engine mounts? maybe under load it is slamming the 02s(or your wideband) into something, or moving and messing with a harness/fuel line

Plugs look great, misfires are 0 because of the P0300 deletion for the cam, I'm going to put that code back in the PCM and see if I have a misfire under load.

Well, looks like I found the problem.....................

It was either A or B, or a mix of both:

A) front fuel log was loose, #1 injector was partially popped out, but no fuel leakage

B) Wire #6 was rusted under the boot at the coil, sanded the coil terminal down, ordered new PRJ's.


Car's running strong now, time for some tuning

Thanks for the help guys!