Thread: P11 Power Loss Issues - Need Help/Suggestions

OEM MAF and spark plug wires just arrived. Will try and swap out on Thursday after work.

Finger's crossed!

Branden
aka hawaiiaNX

And?

OK so here is where I stand as of now:

- Installed OEM MAF (22680-2Y001) and spark plug wires.
- Reset the ECU by leaving unplugged from the battery for a few days.
- Car still hard to start sometimes but does run quite a bit better.
- Once started (while cold) response is pretty much what it should be. I can spin the wheels in first if I rev it up and pop the clutch. Drives well. Throttle response is pretty spot on.
- Once it's been running at normal operating temp for a little while, very light throttle response is still as it should be. However, half to WOT still feels like it kinda falls on its face from 1k-2.5k rpm a little bit. Revs good once past that area.
- Once i've been driving for a while (either cruising down the highway or stop and go in town), starts to really lose throttle response if pushed anymore than light throttle. If I keep driving, car starts to hesitate and buck pretty bad. Backfiring and everything.

Now check this out. First time it started happening I was driving in town. Stopped at a light after driving for a while and when I went to move it started to buck pretty bad. Turned off the car and immediately turned it back on. Throttle response was back to normal. No bucking at the same throttle level.

Next time that it happened I was using Cruise Control on the freeway. Car started to have little hesitations so I took it out of cruise and was manually controlling the throttle. That was fine for a few minutes but then car started hesitating again. So, while still moving, I put the shifter in to Neutral, turned off the car, and then turned it right back on. Throttle wasn't hesitating anymore, even if pushing half to WOT range. Still not much power....but no more hesitations.

Not sure why turning off the car and then turning back on would affect anything. And it's not like I turn it off and wait for a while before restarting. It's turn off and immediately back on and everything seems to be pretty good. Hesitations go away for a while.

Soooo.....any ideas?

p.s. I have an exaust leak between the primary and secondary of my SSAC header. It's after the brand new o2 sensor though. Used the cheapo gasket that came with the header. Saving my brand new copper one for when I swap the RR back in....sometime next year.

Branden
aka hawaiiaNX

Since it's OBD2, do you have anything to monitor the electrical values with? Or maybe even read a pending code? Sounds like you've got some diagnostics to do..

I do have access to a really nice Snap-On scanner that my friend just bought. Gonna try and use it to check out the G as soon as we both have a chance.

Oh, one more thing to note. Not sure if this matters at all but figure I might as well mention. I have the stock, dual out muffler/catback on the car still. The left port of the two coming out of the muffler barely has any pressure coming out of it at all. Could that mean muffler is clogged or causing some sort of back pressure issues? Could high back pressure even contribute to the issues i'm having?

I was gonna try and disconnect the axleback and drive around for a bit to see if that affects anything.

Let me know your thoughts...

Branden
Aka hawaiiaNX

what does your TPS tell you? you should be able to pull it from consult or similar. Sounds like something I had when my TPS was going out. was fine cold, warmed up everything went to hell and bucking ensued.

Hey Zen,

I just swapped out my TPS last night with a spare one that I had in my parts bin. I haven't run into any hesitation issues yet, though I have only drive short distances so far. Really need to find some time to use my friend's scanner. Gonna try and get some work done this weekend since it's a long one.

Will keep you all in the loop.

Branden
aka hawaiiaNX

Just a little update, since it's been a while.

Still having the same issues. FINALLY got some codes off of the ECU though (P0100 - Mass or Volume Air Flow Circuit, P0171 - System Too Lean).

Upon better inspection, I discovered that my negative battery cable was loose at the thermostat housing ground bolt. Like, not even finger tight. Just a few threads in. I have since tightened the bolt and reset the ECU (unplugging the battery method) with no noticeable changes in symptoms.

Is it possible that I fried the new OEM MAF that I just bought and installed? Maybe even the ECU? Would that be on the right track? Anything else that I could have messed up in this instance? That seems like a major ground to the engine. I have not had a chance to pull the ECU and crack it open to look inside. Will do after I get back to my shop today after work.

Also, I already ordered a new OEM MAF and am currently waiting for it to arrive.

Any other ideas, please let me know.

Thanks all!

Branden
aka hawaiiaNX

Brandon, if the ecu is toast and its a 5speed let me know I have a b15 01 ecu I can put in with your filter relocation.

Definitely a 5-speed. Do you know if they run the same ECU? I know they have the same engine, but I have never seen a B15 ECU and have no experience with them.

Oh, do the B15 SE's need the ECU's reprogrammed to the matching keys?

LMK!

Branden