So this has happened a few time in the past month:

Sometimes after start-up it starts up perfect and when it warms up it idles at 700-800 rpm. Then when I start to drive under throttle it won't go past 2000 rpm, instead the fuel cuts and the car bucks and then repeats, after about 10-20 seconds the problem stops and the car runs normally. This has happened about 4 times the past month.

2 other times it has happened while driving. While driving under slightly harder throttle the car bucks like previosuly mentioned and won't go past 3000 rpm before the fuel cuts and the rpms drop then if still under load it goes up to 3000rpm and repeats. Again after a few seconds the car runs fine again.

I replaced the fuel filter this week and when I checked, the gas coming out was brownish in colour. The fuel lines seemed like they were in good shape when I looked at them.

Anyone had any experiences like this? I did search and didn't find much of a similar circumstance, figured it couldn't hurt to ask.

Thanks.

 

Like this? Link to short video

This was caused by a worn out short range TPS..

 

most likely a TPS issue. test out the TPS and if that checks out ok and you still have a problem post back here.

 

We had already replaced the TPS and it checked out. That was a few weeks before this started happening. I'll check it out again to see if it went soon after.

 

if it's not TPS it is still very likely to be electrical related.
are you getting a Check Engine Light at any time?
if you are try this to get the CEL error codes:
http://howto.globalvicinity.com/gv_w...i=39&co=1&vi=1

if that doesn't help then start testing what could cause lack of fuel. check injectors, vac leaks, etc.
might also want to check the AFM.

 

Thanks, I'm not getting any check engine lights and the motor is a fresh rebuild where injectors where checked and all that. I played with the AFM but I'll try checking that again as well as the TPS.

I noticed it only happens when I first start driving after start-up or within 1-2 mins after startup, never after that once it's warmed up.

 

It could be the cheezy clip-on ground from the bell housing to the firewall.

That connection has to be firm bright metal-to-matal solid contact.

If it is less than solid, your sensor signals will all get noisy.

 

Thanks I'll try that later on as well.

 

hmm, if it's consistently the first minute or two it could be something to do with the warmup cycle.
check the BACV (do the test in the FSM).

 

The same day we replaced the TPS is the same day we found that my BAC was toast to, so that has been replaced as well. I'm going to have to give a good thorough check of stuff.

 

Well the car really went bad. I was cruising along when it started to burp a bit and then it did all the symptons above. It eventually stalled out. It happened to stall out just around the corner from the Mazda dealership I deal with. Then the second I popped my hood a CAA truck rolled by to give me a hand. The car was begging to goto the dealership. I didn't have the time to dink around with it with exams and all so I said to just drop it off.

1 Hour of labour and it was fixed. Solution:

As it says on the bill: "Found idle switch to be stuck in the idle position, free up and lube switch mechanism"

Its been better then ever. I guess over the past few weeks it was starting to "seize" up and eventually just did?

Hope this may help some people in the future.

 

idle switch? what does that refer to exactly?

 

The only "idle switch" I can think of is the TPS.
Or maybe the AAS switch on the gas peddle.