help: running rough

[joshyd-mk2gti]

hey,

my car had been sitting in the garage for about a month. i came back the other day and it started first go, i was surprised the battery wasn't dead. drove around on the weekend, did about 100km and it was fine. sunday night i was driving back on the highway and it started surging evey now and then. it was doing it in any gear and at any rpm. it was doing it in town and on the highway, seemed to do it more when going up hill.

the next day i started it up and it started fine. it idled perfectly for about 20 seconds then started going rough, it idled like a tractor. i let it sit there idling for a while but it didnt get any better. drove around the block and it ran like poo. it was going chug chug chug and there was no power.

spark plugs, leads, transfer pump, timing belt are all around 20k kms old. i havnt changed the fuel filter yet thou, could that cause this?


does anyone know whats wrong with my car???? what would cause it to idle fine for 20 seconds then run like poo??

thanks in advance..

[BlackVr6ix]

crap fuel, get a bottle of nulon octane boost and a bottle of injector cleaner and that should sort you out.

[joshyd-mk2gti]

na pretty sure its not the fuel. been on the same tank all weekend, and it was fine for the most part.

any other ideas?

[h100vw]

lambda probe problem?? 20 seconds would be a bit quick for it to warm up but it might be the problem.

[joshyd-mk2gti]

oxygen sensor? hmm. i think the one in it is pretty old and crappy, needs replacing, but i dont think its causing the problem. i started the car with it unplugged and the problem was still there.

it only idles good for around 20 seconds after its been sitting there for a while. if i turned it off then straight back on, it will be rough straight away.

[benissatan]

you sure its not the battery? check the cables and wires surrounding it. thats what happend to my audi. it was creating power surges and it also sounded like a truck in idle.

[joshyd-mk2gti]

good thinking. i think the problem has something to do with the battery/wiring. the other night when i was on the highway, the surging seemed to go away when i turned the heater off. i might try a battery from another car and see how it goes. ill check all the grounds too. cheers.

[benissatan]

yeah, all my wiring had erroded for some reason i dont know how..

its just a simple and easy problem to fix new battery and a general clean up around the battery.

[joshyd-mk2gti]

the problem is still there, i havnt had a chance to try fix it (car is back home parked in the garage, and im only there a couple times a month). i think the alternator is causing the problem, think the pulley has had it. does anyone know how to test the voltage its putting out? if so, could you please explain it thoroughly.

i read that a way to see if your alternator is working is to start the car then remove one of the battery terminals. if the car stalls then the alt isnt working well enough. is this safe to do? as a simple test, should i try it?

cheers

[syncro]

i read that a way to see if your alternator is working is to start the car then remove one of the battery terminals. if the car stalls then the alt isnt working well enough. is this safe to do? as a simple test, should i try it?

cheers

Don't do that. Could fry a few things.

You will need a meter.