Lumpy acceleration = new throttle position sensor?

[Jewson172]

Right I had a quick search and found nothing. A couple of months ago I had the usual sticky throttle, so I cleaned the throttle body out and all was fine. Now the last 2 days the car has developed a weird idle problem, l try and explain it the best I can. On light acceleration through town mainly in first and second gear, below 2k and idle speed the idle drops and it almost sounds like its running on 3 cylinders/ misfiring. So I give it a rev or accelerate harder and it picks up and all is fine. If it doesn't do that the car jerks like its about to stall.
Now as a guess I think it the throttle position sensor am I right?

 

[Silent_Scone]

does it misfire from standstill? if its throttle position sensor it'l misfire on random cylinders

 

[Jewson172]

yes it does and also at low speeds like 20-30mph.

 

[fraz101]

Have you removed the spark plugs? sounds like water in the plug wells or corroded plugs

 

[Jewson172]

No i have not. Ive brought a new sensor (only a tenner on the bay) so ill have a look at the plugs while ive got the bonnet up. I hope i dont find water though :dapprove:. The car drives fine apart from the intermittent rough running. Hopefully ill sort it and be a cheap fix. Keep any ideas coming though.

 

[Reilly.]

I have the same problem mate so please post up if changing the sensor works dude.

Cheers

 

[Jewson172]

Will do, I'll be sorting it out this weekend as its doing my head in now.

 

[Rob669]

Good luck. I've been trying for five years to fix this problem on my Ph1. Over this time I bought four second hand throttle bodies (paying £10 for each one so no great shakes!). I rebuilt one throttle body (taking it apart and polishing/lubricating it), I also replaced the Idle Control Valve, cleaned up the TDC sensor, replaced the plugs and leads, replaced the position sensor etc etc. It eventually goes all jerky and lumpy again. I am lucky enough now to be able to afford a brand new throttle body so that's the plan and hopefully it'll be good for the next five years.

 

[fraz101]

When i first bought mine years ago it did the lumpy idle and stalling at junctions,then my accessories belt shredded and jumped the timing a few teeth so removed the head and put 16 new valves in her,ground them in to perfection,rebuilt the head and it's never once done stalled or jerky idle since!!!!!!

 

[Jewson172]

Update: Right I tried the sensor and no luck. If enything it made it worse. So i WD40'd the mechanism that goes inside the throttle sensor, through the throttle body and to the throttle cable. and lubed up any other moving parts around it then chucked the old sensor back on. It has not fixed the problem by far but the last day and a half and it hasn't done it as much. I dont realy know where to go from here but reading all the other comments it seems like im just going to have to live with it or take it to a garage.