Lumpy / Poor Idling Golf MK4 1.4 16V

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Hi All

Replaced the temperature sensor but Engine still idles poorly! Have run out of ideas now! Anybody have any other views or suggestions as to what the problem(s) is? Many thanks.
Hi Burnerman

No, No Black smoke at all. Sometimes the car Idles smoothly say for 5 Minutes and then start jerking / juddering when say stopped at traffic lights etc!
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As everything seems to have been investigated now, I'd have to suspect old favourite the throttle body....the unfortunate thing is, expect to pay around £150 for a reconditioned one, and those from a breakers aren't guaranteed to be much use either.
These things are given a hard time because the idle speed, to reduce emissions, is kept very low - often between 600 and 700 rpm. Engines don't like to run as slow as this really!
In really bad examples, the engine management comes on as the engine stalls, but the thing always restarts afterwards.
One final point is to clean all of the engine earth terminals in the fuel injection area and check for vacuum leaks from any of the small diameter rubber pipes.
Thats all I can think of, anyway - and I'd be delighted to be proved wrong!
John :)
Dear Burnerman

Many thanks for your and all the other help. I will certainly go over all the steps to ensure I have not missed anything and will work thru the Haynes Manual to see if it sheds any light.

Throttle Body has only done 40,000 miles would it go at that Mileage? Also the RPM's are rock steady at 900 even when the car shakes and is lumpy!

Could it be the distributor which is not the coil pen type?
Distributor wear is certainly a possibility - start by taking the cap off and see if there is any up and down movement in the rotor arm shaft.
If you have access to the old fashioned strobescope lamp (now there's a blast from the past) you could see, by pointing the light at the crank pulley timing marks, whether the timing is moving about at all.
Failing that, I can only suggest that you visit a diagnostics centre (not a main dealer) somewhere local....the chances are, they've come across this before.
40k plus miles isn't a huge mileage, but its throttle movement that really matters....on a city car, this is likely to be more than on a motorway car.
John :)
Hi Burnerman

Thanks for that, there is no distributor Cap or Rotor Arm as its electronic. Could it be this module attached to the camshaft that is the problem?
Ok - I was under the impression that the car was the older type.
All I can say is that I wouldn't be suspecting any part of the system that was solid state electronically - in my experience they either work or they don't.
The throttle body does have a carbon wiper (a bit like a potentiometer if I recall) and as the resistance track wears then things can get somewhat out of kilter.
What I don't want you to do is to start just chucking parts at the car as ten to one it will cost a bomb this way.....a genuine diagnostics expert could use an oscilloscope to check the output of the various components but thats beyond the reach of the genuine DIYer.
If you can check out a firm called BBA- Reman you could get some hints there.
John :)
Thanks Burnerman, True Gent, will look at the Site and do some more rearch.

I too am of the opinion that the Throttle body maybe be at fault. Chap from Kwik Fit said that they always replace these whenever they get these cars with uneven idleing etc.
I can only wish you luck mate - as with all of these wretched faults it can be an expensive gamble!
John :)
Did you ever succeed in getting the car to behave
Could it be the small hot/cold flap in the airbox?
I've Got the same engine and same problems ( bought the
Car with the problems yesterday, and Will Soon start to investigate my own)
Just ising the Web to find out what helped others, and it seems that you haven't posted Any solution;)..
Best Chris
Welcome to the forum Chris, don't think you'll get away with a sticking flap in the air box, but hopefully you will
Hey Mursai..
No i know;).. Just searching the Web and try to make
Ppl give an Update Wether they *FIXED* it and what their solution
Took my egr pipe off, Egr pipe, TB cleaned Them all, no luck
(Although i couldnt Rehling egr via vcds afterwards)
Besides that the former owner had the oil Cather replaced, oil pressure sensor changed, head removed ,Oil pump replaced.. Breather pipe changed,
But to no avail.. ( the car Also had A red light and puzzing issue when driwing around 1500 -2000rpm, on the freeway the oil light doesn't flash )
Best chris
Hi Chjee / Folks

Apologies for the length of time posting a reply as I have been abroad till a month back! I have not found a solution yet! My Compression test showed no problems. Car would run smoothly from start but when it reaches normal operating temperature it would sometimes misfire always cylinders 3 & 4 even when coming of a motorway and stopping, it would misfire at idle!

This is the strange thing! When car is stationery uphill the hill the engine rocks back and forth noticeable! If it is stationery downhill 9 times of 10 it is smooth as silk! I have changed the fuel filter, Spark Plugs, Leads, Temp Sensor, cleaned throttle body, EGR Valve but same old problems.

Had a Lambda sensor problem with sensor near Cat replaced that with a generic sensor (Lucas make) Now get get CEL fault short to B+ whatever that means! One mechanic thought it might be fuel injector intermittent fault!
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