* Update *

I took it for a drive and what it does exactly is at normal throttle acceleration (5-10% throttle), it bogs down until the rpms dip then takes off again from a few hundred rpm. I put it in first gear and just held the throttle at a steady input and here is what it does: Mazda Protege Bogging Problem (unsolved) - YouTube

If I cycle the ignition during the bog phase it takes off like a bat out of hell with no additional throttle.. as shown in the video!!

* End of Update *


Hello I am trying to diagnose the problem with my friend's Protege. It's a 1997 Mazda Protege with the 1.5 DOHC engine.

She has changed: PCM, MAF, TPS, Fuel Filter, Distributor Cap (not sure about wires but they look fine) so far that i know of.

The car starts fine and idles around 1.3k RPM. At times it idles around 300-500rpm. If I drive it down the street from a cold start it kind of takes the gas but after a minute or so it gets to a point where any bit of throttle bogs it down and it literally stops accelerating.

If I go down the highway with it this is what it does.

From stop: Takes off ok with hardly any load (it's a standard).
Press gas to drive normally: Car falls on it's face and slows down.
Let off gas: Car picks back up speed but doesn't have much acceleration other than idle speed or just above idle rpm. If I upshift into higher gear and "NURSE" it, I can get up speed with other cars it just takes a little longer than the rest of traffic.

Exceptions: there are times (often) if I can get the RPMs high, like 3.8kRPMs or higher, it will take off and I can give it full throttle and it accelerates wonderfully. If I shift around 4-5k and it drops to around 3k it sputters a little but takes off again.

If I give it wide open throttle during the bogging phase it does nothing normally, it just bogs more but SOMETIMES, and I mean sometimes if I give it lots of throttle it will hurry out of the bogging phase and actually take off.

Last night I was pulling off onto the highway and I gave it alot of pedal and it fell on it's face, then took off urching the tires, then fell on it's face, then took off again urching the tires again, then fell, then took off and kept going like it should.

Feeling: It feels like there is a complete dead spot in the throttle pedal *At times* where pressing the throttle makes it slow down or lose speed instead of speed up.

=================================================

There is no check engine light on, except for last night it came on after I cleaned the MAF, and changed the TPS. Gonna go try and figure out why the light is on now but before it was NOT on and ran for a long time as described above without triggering a light.

P.S. It acts like it has two modes: Idle poorly, bog on any acceleration mode or Idle perfect and accelerate nicely.

I know this is long but if anyone has a clue please chime in!!

 

After a thorough post with video and 75+ views i thought sure this would get a reply

I will leave this info for future troubleshooters. It wound up being that the tps sensor was good but the minimum voltage was not being met. Whoever installed it had it set too low.

It was set to .15volts at closed throttle. I bumped it too .50volts, reset pcm, and she drives way better. Now I just need to make it idle stronger because the a/c nearly kills it at

 

bolt: I was one of those who looked. It really stumped me. Thanks for following up with the solution. I don't think I would have ever thought of that. I learned something.

Thanks again.

Tan

 

Bolt: I am having the same problems that you just described in your post how did you set the TPS to the right voltage because going right to left throughout all I get is 4.8 it's a brand new sensor