Car is bucking??Help

[purplemx3gs]

Ya i bought this 1996 MX3 GS V6, and its bone stock, except for cone filter. I have put new plugs, plug wires, and new distributor. My problem is, whenever i go up an incline or when the car is under load, it sometimes kicks or bucks, normally once or twice, sometimes 3, 4 and 5 times, and normally at lower rpms, rarely at high rpms. Sometimes they are hard bucks, sometimes soft, sometimes just feels spungy like not enough power or something. The CEL came on a while ago but then went off. It did that a few times but hasn't for a while now. Another thing i noticed was one night i was driving on a straight flat road going 85 kph, the rpm was at around 2600, but i noticed that when i kept the gas extremely steady, the needle moved up and down at random times. I thought that was kinda weird. Can any one please help me??? O and one other thing... on a cold start like in the morning or something, a car is normally supposed to idle higher, well mine idles the same say as if it were hot, so sometimes feels like stalling. All of this doesn't happen ALL THE TIME just sometimes and its annoying.

[slimmyslim1420]

You could possibly have a vacuum leak or maybe your TPS is either off or bad. You say you have a 96 is it OBD2? If it is you could try to read the codes even though the light is off, you might come up with something. It would be worth it to try anyway.
Goodluck.

[Vanished]

If its OBDI or II all depends on which month it was made.

I'll tell you now tho, you might as well try and pull the code, because it's still stored in your ecu somewere.

The same type of thing happened to me. My cel came on, then went off. And now my car bucks, especially in first gear with my foot off the gas at low low low rmp. The code that i pulled was the TPS code, and i have yet to replace the TPS, but i'm pretty sure that is the problem.

Also look for vacume leaks. To do this, spray some WD40 around the possible vacume leaking areas. Do this while the car is running. When you hear the rmps go up, you know you've found a leak because its being sucked into the engine.

Good luck man

[purplemx3gs]

Ive tried several times pulling the codes but 2 scanners cant get anything, and ten to gnd or watever wont either. Its weird. Im going to a garage today to talk to a Mazda tech and see wat he thinks. Thanks for the imput guys, i will definitly give them all a try!

[purplemx3gs]

The car is still bucking, i changed the fuel filter also but no go. One thing i just noticed yesterday was on a cold start, it idles at 500 right away, then without touching the gas i wait for about 4 - 5 mins and the revs go up to 1300 and then very very very slowly like 7 min range they start to go down. Im wondering if my TPS is going and if it is, would that be causing the bucking problem?

Ill just go over the symtoms again. ---Only on low rpm while accelerating under load will it buck, like up a hill or small incline. Rarely at high rpms but sometimes just light bucks (feels like im on and off with the gas) the hard bucks feel like the engine shuts off and then back on... This doesnt happen if i drive the car easy and normal, its only when im pushing it a LITTLE. Please Help!!

[PATDIESEL]

I'd say you need a TPS adjustment or replacement. It also could be vaccum.

Slim said the same thing so I'd start looking at these things first.

You can do a search and find how to set (adjust) the TPS.

[mx3_rider69]

sorry wats a tps is it a temperature sensor?
i got almost the same problem but my only bucks when the engine is hot it tends to stall and bucks or misfires when i press on the gas i already check for vacuum leaks and replace the engine coolant sensor and i cant find the problem plz someone here help me!!!!!!!!!!!


ok sorry i got it now throttle position sensor ok now is the trothle position sensor same things as a speed sensor sorry not to technical!!!

[purplemx3gs]

replace the oxygen sensor!