car was bucking today
 

Here's the story,

I went to mazda today to get the timing adjusted and the mechanic checked some stuff out, sensors, compression... he checked the TPS and said that the voltage is supposed to change when you press of the gas pedal, which it didnt do and that my coolant sensor was to changed. I leave the dealer with the car, and after 15 minutes (65mph on the highway) the car started bucking like hell ( accelerates, stops, accelerates, stops pretty fast). I let it cool down for a few hours and start it again, no bucking at all. Now im home, not feeling like taking the car.....

funny it started after the timing was done......it might also be an explanation.....

is my TPS to change? and is it the cause of all that bucking????

another thing, compression tested low (engine has 1500miles on it (3mm seals)... around 5.0kg/cm per chamber on each rotor.....wtf?????

A tps with a intermittant *open* in it will give you symptoms like you describe. The tps gets heat soaked and fails. You let the thing cool down and it works again. Mechanic is probably right about the tps being bad.

One thing the tps does, is tell the ECU when you let off the throttle completly and that the throttle plates are closed. When this happens, the ECU cuts fuel to the primary injector. You won't notice this if everything is working properly. BUT, if the tps is so out of whack that it incorrectly tells the ECU that the throttle plates are closed, when they in real life are not, then you will get the studder, shake and bake problem you are experiencing. That my story and I'm sticking with it.

well, thks a lot, I'll be heading to my parents get the TPS on my spare engine...

Hailers, or anyone else, is it possible to test the tps with the car moving? I get an intermittent mad bucking, that only happens when I'm city driving, which has me thinking heat related. the tps checked out fine, but if I could see it drop or spike or something when hesitating that would be good...

Charlie

My T11 has this bucking problem when it gets hot also, but the funny thing is, its without the TPS connected. WTF?