tdrimer

I still can not figure out my issue. Everything has been changed or checked on this car, so really thinking its tranny or clutch. The car going up through gears just has this bucking going on. But it's getting worse and now I have found a pattern. In first gear seems ok. Second gear (does have bad synchro if switched before 4k rpm), the car has this long sort of bucking sensation...meaning it is a longer type of hesitation as it goes up through rpms, then when I switch to third and get moving the bucking is much quicker, 4th gear not much different and don't really feel in 5th as I don't use much or am cruising.

This pattern happens every time which is why I am thinking clutch or tranny? Typical clutch slipping is not happening... Would a warped pressure plate or something cause this sort of issue? I have not seen online or talked to anyone that has ever had this situation. Could the chip cause this issue? Bad FPR? (But would FPR actually have a pattern...same with maybe clogged injectors? Wpuld those have a pattern in different gears?) Nothing I am reading on symptoms for tranny and clutch discuss this. Plugs, wires, afm checked and fine, o2 sensor changed, distributor changed, etc etc etc... But I can't imagine any issues with those would create a pattern that happens every time now?

Help...I am going crazy.

I am buying a 996 as well so I want to get my 44 turbo fixed once and for all!

fejjj

Have you changed your TPS?

Does it back fire?

tdrimer

Every once in a while I hear a pop going into second but nothing beyond that. It's a small backfire. The TPS has not been changed

Brantley

Maybe failing knock sensor? Give that a check. I can't remember what the proper voltage (or is it resistance?) is out of it... The wires 11 through 13 to the KLR can be tested. One of them is the ground..

Failing knock sensor can cause the car to run like crap / loss of power. Possibly more extreme than what you are describing... so just another possible thing to check.

NM'87 951

Leaky injectors caused hesitation on acceleration with our 87. If you haven't gotten there yet.. or have to down the line..

Willard Bridgham 3

Check all connections on air pressure side and check all vacuum connections.

odb812

I'd say you have an engine problem, not a clutch or tranny problem. Most likely you are seeing the bucking quicker in third and fourth gears because you build boost quicker in third and fourth gear.

What is happening with your boost gauge when this happens? Factory or aftermarket boost gauge?

Did you change the rotor with the distributor? If so, how many miles ago?

audisport

Vacuum leak?

tdrimer

All vac lines just replaced...boost gauge seems fine...I think. Doesn't jump or anything. The RPM gauge also stays steady. Just in the last day noticed rpm running slighrly low until warmed up and sitting at light would drop a 100 or 2 then back up?

tdrimer

Ps dist changed under 1k miles. Turbo spools up good. Getting up over 4k rpms in third it is really moving and that hesitation goes away...

CBR944

Have you checked the AFM and O2 sensor? Dropping revs at idle suggests an air/fuel mixture issue. If the AFM is sticking or the wiper contacts are worn it might result in a rich or lean mixture as you accelerate up through the gears. Holding steady might be fine.

George D

Bucking isn't relevant to your transmission, driveline, or hesitation. You are having an electronic-engine management issue. Haven't read the other responses, but this isn't particular to your driveline.

Jfrahm

Bucking is often caused by a crack in the intake somewhere opening up and messing up your air fuel ratio. If the engine is moving around on it's mounts it can pull open a cracked J boot or cause a leak at an IC connector. However it's not clear from your description what bucking really means, to me it is a pretty violent shake as if the motor stopped for a second.

What does the tach do when this happens? Boost gauge? Aftermarket chips? What boost control? Engine hot or cold? It could be TPS, it could be the knock sensor, or it could be that you are overboosting and getting timing pullout.