My 2001 Tracker jerks when starting out under hard acceleration or when cruising over 70 miles per hour. Under normal acceleration the car runs fine. No codes show up.

 

I'm having this same problem except my Tracker will jerk when I'm going 35-40 mph. It's worse when I'm trying to pass someone on the freeway. Checked air filter and spark plugs and both are fine, I'd like to know if someone else has found a way to fix this problem.
Thanks!

 

Bumping this on off chance it gets noticed by someone who experienced (and solved) the issue. Same problem as OP. '02 Tracker ZR2 4WD. Will jerk/lurch/lunge forward and very reluctantly get up to speed after a stop. Will go normal again only if I stop and restart it. This only happens occasionally, but does seem to happen more often when going slightly uphill after the stop. Car will occasionally have the problem while driving (uphill) but again, mainly after stops. Because it is occasional, I can't get a mechanic to experience it. No error codes. I have had the transmission looked at, but was told it is not the problem. I had the catalytic converter replaced; problem has continued. Complete replacement of transmission fluid. Oil changed, new air and fuel filters. Still happens. Any comments welcomed.

 

With old systems, such cases usually involved the ignition system. Higher speeds induce even more stress on the ignition system and so...the problem may then become apparent--as well as going uphill. I would carefully check the ignition system out-----are the coil paks OK, etc... I am used to the old ignition systems and wires. The Tracker is a whole new baby to me. The descriptions of the problems above, however, harken to the old ignition problems---so I "suggest" this may be it? Especially since the vehicles are over 13 years old and ignition systems are not meant to last forever. Since I have an '02 which obviously has the original system, I feel I am vulnerable to this eventuality--I expect it. Any used vehicle I ever bought--the first thing I did was to change out the plugs--wires---cap and all of that. It always prevented sudden surprises--like the vehicle won't cold start in damp conditions.

JR

 

It turned out to be the Mass Air Flow Sensor (and possibly Throttle Position Sensor). After trying everything (including fluid replacement, filter replacements, cat convertor cleaning, almost having the transmission rebuilt), I had a mechanic recalibrate the Throttle Position Sensor, and then bought an OEM Hitachi AFH55M-13 Mass Air Flow Sensor, cleaned it with MAF cleaner (Autozone) and had the mechanic install it ($100 for the part on Ebay, $50 for the installation). This solved the problem. According to most, an aftermarket part won't work properly and the problem will continue, so get OEM if you have this problem.