the only other things i have not yet done is

took out ecu and clean all contacts

and the rotor arm

but i am not sure how to check these things

The rotor arm is inside the dizzy cap and just plugs in and out (same colour as dizzy cap so cant go wrong)... dont pay more than 5 quid for one.

To check the potentiometer I took it off.. In therory if its shagged the car will stay the same, if its fine the car should go crazy. Mine went all jumpy when I took it off..

The ECU just unplugs, I took my chip out and back in and just checked the pins on the ECU to loom.. if they were dirty i just scrapped the crap off..

I still dont know how to reset the ecu? DOES ANYONE KNOW???

The jerking could be the throttle potentiometer.

that will be the problem me thinks too ..

Hi, Just bought a cheap ass GT.. Engine has 120k but pulls like a train and very quiet.. But it sometimes kangaroo's.. I.E.. i'll be driving along and it will jump like I'm pumping the accelerator.. It mostly does it on hard accelaration? But only does it for like 5 secs then its fine? and only does it sometimes? The entire 150 mile drive home was fine! I've checked all the earths and connections.. All Seem fine.. The car is due a service but looking at the oil, plugs and HT's all seem ok still..

Anyone know?

sorry if someone said this but i had a similar prob on a gt it was the air flow meter also i changed the fuel filter and checked pump was ok too all went fine after that

I disconnected the potentiometer and it hardly made any difference, when you say crazy what should it do, i only disconnected it for about 5 mins when the car was a little warm, does this make any difference, shall i disconnect it when the cars very warm, or wont it make any difference.

when you say

Mine went all jumpy when I took it off..

what do you mean, the jerking goes worse?

If you disconnected the potentiometer on idle.. its unlikely to make any significant difference I guess. It senses how much you open the throttle by! I doubt its drivable with that disconnected... surely!

Have you bought a haynes manual yet?

My idle went all over the place and I could hardly drive it! If yours doesn't do much when you unplug it maybe its on the way out?

I took it off when it was a bit warm.. about 5-10 mins stood still.. when i unplugged it the idle went from 500-1500 rpm and back down again.. when i tried to put my foot down (car stood still) it kangaroo'ed very badly. I didn't drive the car like this as i doubt I would get far as I couldn't even rev the engine without it jumping!

Hope that helps!

Edited 27 July, 200719 yr by MrP

yes i have got the haynes manual

when i disconnected it I could still drive it,

my idle speed does mess up alot when warm but it does that normally anyway, my revs stayed the same,

i think it is on the way out, does anyone know where i can get one from or anyone selling any cheap.

thanks

I will ask my mate.. he said VAGspares?? or something like that.. £35.. I'll ask him for you to confirm the details.

If that doesn't fix it I'm stumped?

Edited 27 July, 200719 yr by MrP

Also.. I've been told that when you do change the Petentiometer it needs to be set up to the ECU using diagnostic software.. But all my mate did was reset the ECU before fitting it!

have you managed to reset your ecu yet? how did you do it

I've been told to take the ecu out and leave it overnight? I assume so the power runs out and it looses its memory?

on most cars I've owned you unplug the battery and then put your foot on the brakes for a while. worth a try?