rough throttle - JERKY GEO

[GeoMetron]

My metro has suddently developed a problem in maintaining a current speed. If I let off the accelerator and then reapply it, the car jerks forward, sometimes quite violently. The problem isn't as noticeable at speed, but in lower gears and in heavy traffic, it is very annoying.

My throttle cable feels a little loose, but without a frame of reference I'm not sure how loose or tight it should be. The accelerator pedal seems to move a fraction before the throttle engages and when it does it is never with finess.

Thanks for any assistance,

GeoMetron

[mickkey3rd]

Greetings

My 92 has the same problem, have you had any luck finding the cause?
I noticed mine only does it when the weather is warmer. Which may point to the IAT sensor. I checked it and it works fine The ECM regulates mixture during coasting, so this may be a clue. I will let you know if I find out anymore.

Joe

[GeoMetron]

Well, I was hoping that others might chime in so that I'd be more confident that my diagnosis was correct.

It is almost certainly my TPS sensor. I replaced it with one I got off of ebay. It solved the problem. So you might try that.

Geo.

[mickkey3rd]

Hi Geotron

Most interesting, I recently adjusted the throttle stop screw. This stopped the dramatic drop in speed, when I let off the accelerator and the sudden jerk when I pressed on the accelerator. Now my idle hunts
a bit. I will double check my TPS to make sure it is within specs.

Thanks
Joe

[Lemming]

Problem: When the car warms up (ie driving awhile, or warmer weather), and I step on the gas the car "bucks" (jerks, whatever).

Soloution: Check you ingition coil for corrosion. To find the coil just follow the the center wire from the distributor cap back to it's source, pull the plug and check for black carbon, rust, melted plastic, all that junk, if you find any thats your problem 100%. This can be caused by a bad spark plug wire. whats happening is as the coil warms up it starts to arc and therefore does not send current down to the disributor. If you have a 3 cyl 1.0 expect to pay around $150 (Canadian) for a new coil (Note: there is only one coil). The job is an easy fix, just unplug 2 wires and unscrew 2 screws and you're done.

If thats not your problem (it probably is though) check your plug wires, plugs, and disributor cap. Each kit of replacement parts for these things can be had for 30 bucks or less (Canadian). If you find you have to replace the coil, I recommend changing all of the above because one of them will be the reason the coil went bad in the frist place.

Hope this helps, sorry it took so long for me to see this thread.

[Lemming]

Just to add to my last post here, after all that, distrubutor change time....