Vertigo RT

Hey guys,
First off, thanks for everything so far, Ive read a lot about this car and its... ermm... habits?
But, Ive got this one lingering issue that seems to be getting worse as time goes on.

The car will drive normally and then itll seem to lose a little power and get intermittant at higher RPMS... the car will then make it until (usually) the next red light, and either stall out when the gas is pressed or will `skip` forward, between 0-3000rpm hopping.... after which it will always shut down.
At first, turning the car off and resetting the NVRAM would suddenly cause the car to run great again for the next 30mins or so...
Things I know: It seems like its worse in the heat of the day (Florida), The A/C seems to hasten the process as well. When it does the jumping thing and the stall out it doesnt seem to be a misfire, as the CEL does NOT blink...
It can do this several times, and not throw a code... but when there IS codes...
I got: p0171 (once), p0442 and p0455.
I cleaned the MAF and TB which got me several LOUD backfires and then reset the CEL and NVRAM...
The car for the first time was able to rev high enough to BEEP (didnt even know it did that)
Drove it about 3miles and it stalled again, and were back to it dropping revs after 7500 range.

My first thought is bad fuel pump, but as these cars run VERY different than a standard Vpattern or inline, I figured Id ask for some advice
Thanks!

Vertigo RT

Also, when not in gear and revved it backfires quite a bit, but I figured that was due to the test pipe thats installed...
The car is otherwise stock.
95k, 6spd GT

RIWWP

iTrader: (2)

All 3 of your codes point to a vacuum leak. This can also produce all sorts of weird behavior, depending on where the leak is.

You probably have something else wrong as well, but find and fix that vacuum leak or trying to trace any other problem is going to just be a wild goose chase.

Vertigo RT

Gonna go take a look now, thanks!
Smoke test is the best idea I got for chasing down a vacuum leak... any good place to start?

Looked around for vacuum leaks... cant seem to find any.
The car will rev to 8000 and come back to 6000 and loop at WOT, with small backfires...
However, when it DOES pass 8k itll be LOUD

RIWWP

iTrader: (2)

Huh? What do you mean?

Are you saying that if you are in gear and have the throttle pedal to the floor, the RPMs will climb to 8,000rpm, then DROP to 6,000rpm, then back up to 8,000rpm, then DROP to 6,000rpm, all with the pedal to the floor?

Vertigo RT

yes.
currently, Im on the side of the road, it started stumble and skip until finally I had to pull over. tried an nvram reset, as for some reason it seemed to help in the past...
this time, if anything it made it worse...
ive got the battery disconnected to see if it can stumble home or something...
while on the road it wouldnt pass 4k... and barely got there.. then finally it acted as if it was getting no fuel and dropped dead

after the negative being removed from the battery for approximately 10mins... then the nvram once again reset the car runs normally... revs to at least 9k (i didnt push my luck)
now for a test drive.

nope... made it less than 2miles.. same result.

now walking, lol

YouTube a short video of what it did before I left

the thudding is my foot between 0 and WOT... youll notice it doesnt correspond to the rpms

Mod Edit: Posts Merged

RIWWP

iTrader: (2)

Video is private. I'm having trouble understanding what you are trying to convey.

Vertigo RT

video is fixed

So, I go to pick the car up this morning... and it runs fine again... wtf?

From what I'm reading, it looks like it may very well be the fuel pump overheating. Thinking on it, it really only seems to be superbad when the fuel level is below a qtr tank, or the fuel pump is being run hard (wot, high revs)
Anyone agree that to be likely?
The cars failure seems to be pretty independant of the CEL.

RIWWP

iTrader: (2)

Ok, I got back home, been traveling for the past few days. Merged a bunch of your posts.


I saw the video, and this isn't a fuel pump problem. You return to idle every time, a failing fuel pump would just cut off the engine completely.

If you really are putting your foot to the floor in neutral like that and the throttle is simply not responding it appears that the ECU is taking over and killing throttle input. The only reason I've seen it do that is if it's held at higher RPM in neutral for a while it will kill the throttle input to prevent overheating of the engine and exhaust (There have been a few vehicle fires in several Mazdas with this, and they implemented that across all Mazdas). I have triggered this personally a few times, and I don't see the right behavior there to believe that this is the problem.

Pull your intake and have someone manipulate the gas pedal while you look at the throttle body butterfly (with the key to "on" but the engine off). See if it's moving in direct relation to the pedal or not.

Vertigo RT

butterfly doesnt seem to be a problem... you can still hear it open and close when its doing it, as the intake sound changes.
the car does die unless you keep slapping the gas pedal that way...