Anywhere between 2-3K rpm the car has a tendancy to buck when off the throttle. Just tonight I pulled the codes for both narrow and full range TPS, could this be the problem? Also, just got my o2 sensor rewired ( I think) could that still be a problem?

 

Yes, check and set the TPS, that could be causing your problem if it's way off.

 

aalso check your driver side mount...

 

how would the mount affect this?

 

it may also be a broken diff mount which causes mild forms of bucking

 

how hard is it to replace these various mounts

 

This is a fairly common problem at low speeds in low gears... it's the nature of the beast.

 

yea i cant pull in my garage in gear, i have to just fly in while in N, other wise it would be a bronco...samething while pulling out, but it could be cause i have a really new clutch >3k miles on it.

 

Mine bucks at about 1200-2400, but not between 2000 and 3000. I wonder if thats just cause yours is turbo and mine is a reliable NA. Definitely check the TPS t make sure its in range.

 

Mine also bucks when trying to keep a steady speed with the rpms under 2k. I thought it was normal, cause the engine has almost no torque at such low rpms... makes creeping along in traffic interesting lol

 

I can cause this to happen on my car by going either too rich or too lean in the low rpm light load regions on my haltech. It's not the way it has to be, mine would do it sometimes before with the stock ecu and old motor, I always attributed it to the TPS being a bitch to keep in calibration. Problem has been completely eliminated with the haltech.

Poor U joints and motor/trans/diff mounts will exacerbate the situation but the origin is the engine surging and hesitating because the AFR is not right at that moment (in my experiences anyways).

Also, having a lightweight flywheel makes the problem worse, the engine can surge and stumble with impact on rpm much easier with less rotating mass.

 

I can leave my foot off the throttle in 1st gear, and the car will just move along at walking speed, as smooth as silk. It's an NA.

 

N/A's can do this just as easily as a turbo people, believe me I know. When the TPS isn't set correctly this will happen, happened to me rather violently until I reset the TPS correctly. Ever since then, no problems at all.

 

yea my car is doing this and it is a bitch -- 1st gear whenever i let off the throttle around 2500 rpms or less it will buck like a ****** bronco so i usually just put the clutch in to stop it... anybody got a link to a forum abou this i know someone does... i dont want to **** up my enigine


how do i check if my throttle position sensor is messed up, i have also heard this could be an o2 sensor problem or that my timing could be offf (hope not!!!) then someone keeps saying that this is the nature of the beast, which i am not content to accepet