1992 Corolla 5 speed manual transmission. 4A-FE w/150k mi.
I recently went to get my car smogged and they had to abort the test due to my car bucking on the dyno when held at 15mph in second gear.
I've owned this car for about two years (purchased @ 120k mi.) and either I didn't ever really notice this issue when I first got it (this is my first manual tranny car) or it came on gradually.
Upon my own inspection I did not find any broken or cracked hoses and diagnostics gives no fault codes.
My inkling was (and still is) that it has something to do with fuel delivery because while the jerking/bucking issue only shows up at certain speeds, it only happens at those speeds when I am barely giving gas. However, I figured there are so many things it could be that I wanted to have it checked out rather than replacing parts one by one.
I took it to the local Toyota dealership proper to have it diagnosed and they reported that they couldn't find any faults other than the engine front motor mount being destroyed and the LH axel's outer CV boot was torn (and the joint had some play). They said that fixing these issues might not even resolve the problem, so it was up to me to decide whether I wanted to do anything about it. Here is the diagnosis they gave me verbatim:
"Condition can be duplicated @15MPH in 2nd gear - Verified complaint. Vehicle surges during driving in second gear usually with foot off of gas.
Performed visual inspection. Found front motor mount torn. Left axle shaft has play. Boot is open.
Checked for codes - none found.
Checked and adjusted timing and idle. Timing: 10BTDC. Idle: 800RPM. They were slightly off.
Checked O2 sensor. Crosscounting normal.
Checked suspension for play. OK.
Recommend replacing engine front and rear mounts and left axle shaft as a first step.
No guaranty this is going to eliminate the entire issue. Potential play inside of transmission amplifying condition."
They provided me with a list of part numbers for what all needed replacing and I ordered them from http://www.toyotapartscheap.com/
Yesterday I replaced the front mount and the LH axle and besides the throttle response being a little more solid there was no change in the bucking issue.
I just realized I haven't changed any of the spark delivery components (plugs, wires, etc.) so maybe that might be a place to start. Next place to look would be injectors? Fuel filter?
Anybody have any similar issues or have any good suggestions as to what to inspect or replace?