Hi I’ve got a 97 mk4 1litre polo,which has an annoying problem
Of once warmed up the revs will dip below idle 3 maybe 4 times
when come to a halt causing gearstick to shudder then ok.
Has been like this for 2 years unable to find out what.
has now started stalling a few times last week. Also rev counter
needle flicks about on it’s on every now and again whilst engine
is at idle?? It’s more annoying than anything but the stalling
is a new thing. Never happened until after getting timin belts
replaced and whole new exhaust from kwik fluffy…? Thanks, mark.
Coolant temperature sensor and throttle body are a couple of common things that may cause the problem you’re having but well checking for leaking vacuum hoses if it’s only happened since you’ve had work done. Worst case may be that the timing marks aren’t properly aligned when the belt was done but that’s unlikely.
Ok cheers, going to take it one of those diagnostic places see what’s what 
Took car to Autohaus @ Bilston glen industrial estate. He said what u suggested, throttle body:). £40 to clean out. Said would run bit high for a week revs wise? Then be ok. Been reving @2k but now down to 1.4k and drops to regular idle in seconds. None of previous probs so guessing that’s it. Been week since been in.
Ok it’s Been couple weeks now n car still revving high. Not as bad as when got back, but still about 1500 revs before dropping to correct idle. Doesn’t have any of earlier faults now though. Now I’ve just noticed wee bit oil under car and when dipped it it’s only showing a little touch @ bottom of stick? Also when looking under car exhaust downpipe seems a funny pale yellow whitish colour? Don’t know if these connected with earlier or been for a while as never really check outwith yearly service cheers, mark.
Not usually problematic for oil leaks but through time that can cause the outside of the sump to corrode and eventually go porous, worth a look. If the engine is really oily then get it steam cleaned to remove the excess oil, this will make it much easier to see where the oil is coming from. Meanwhile keep a close eye on the oil level!
Can’t think that deposits on the exhaust downpipe as being much to worry about, probably just some funny corrosion of a coating on the pipe :think
Certainly sounds like the throttle body is the root of the running fault, cleaning can help but sometimes replacement is required, new units are pricey but remanufactured units are much more affordable.
If you do need to change it then you could probably do it yourself if you have basic tools/skills as it’s not a hard job.
Cheers
Kenny
Cheers:). Checked oil was just on dipstick and no more… Took nearly 2 liters to fill. Now idle only as high as 1100/1200 and quickly drops to regular 900 revs. Hopefully about fixed. Going in fri anyhow for check. Don’t know if low oil any link? ( leak was off another car ! )Thanks, mark.
Car is cured after adding oil was almost back to normal and nxt day perfect. Garage re checked but all ok.
biggrin.gif Great stuff mark, glad you’re all sorted! biggrin.gif