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98 Eclipse 4g63 FWD GST Bucking in gear

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spainobain1234

Probationary Member
9
1
Oct 17, 2013
Puyallup, Washington
4g63 Turbo GST FWD Manual Transmission

Symptoms:
Heavily obvious, I'm driving in any gear when I am 10% Throttle Accelerating, the car bucks like crazy like it is stalling during acceleration. The rpms bounce from 1k-2k rpm, and 2k-3k rpm. In between those RPM ranges, the car bucks even when I am pressing the gas pedal, it is like it Completely cuts the fuel, Rpm's bounce, stops accelerating then kicks back in to accelerate again then bam, no more increase, then rpms drop it slows down and speeds up, bam, while my foot has remained the same constant 10% throttle on the gas pedal.

Every time I accelerate in gear, 10% throttle, the car goes up goes up and STOPS accelerating and makes a clunk while my foot is still on the gas, and the rpm bounces up down and then the car Reactivates in gear and accelerates like it is trying to get back to the same speed then Clunk it stops again and the rpms bounce down and shoot up 1k - 2k 1k-2k car bucking.
The car bucks, and every time I am decelerating, the car bucks at low rpms like 3 times. It goes, buck, buck , buck, and the symptoms are heavily obvious.

Any help appreciated on this thread.
Thank you
 

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The very first thing you should try would be a boost leak test. It sounds like you may have a small leak somewhere.
 
Running No boost leak, replaced engine mounts all suspension control arms, bushings
Bov plumbed back into intake manifold

I need serious help with this issue

I am thinking the throttle body butterfly valve could cause this if it's sticking :-/

I lightly hold my foot on the gas, and don't let the foot move from this position on the pedal
Slowly accelerating very slowly then CHUGGA CHUGGA CHUGGA it bogs down without lifting my foot from the pedal it slows down.

Holding my foot on the pedal

Bucks three times from 2500rpms it bucks three more times and decelerates slower down to 1000 Rpms

Bucks back up to 2500rpms and bucks three times and slows to 1000rpms

Repeats this process
 
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