Hi guys

New to site which is very impressive not sure if I have done this in the correct way for help .

My mk1 1999 1.6 focus zetec has the dreaded idle issue. Basically I so far have replaced the following : pcv valve and hoses,

Idle control valve ,

Throttle sensor ,

Air filter ,

Maf sensor ,

Plugs leads coil,

I can not hear any air leaks .

The car starts fine runs fine at cold about 1200 rpm idle . When warm 750-800rpm at idle if I gently push accelerator at this point it picks up as soon as get to 1000 rpm it stutters and coughs till past approx 1100 mark then all fine again drives fine till I slow up at junctions etc etc again around 1000 rpm will kangaroo jump splutter etc does not stall yet lol any help would be greatly appreciated oh also no engine lights showing either .

Welcome to the family Grant, where abouts in the garden of england are you?

It seems that you havent yet changed the fuel filter. I expect that if you replace the fuel filter this will hopefully help with the issues!

No I haven't done this yet will do tomorrow though thanks I'm in meopham thanks for ya advice will keep posted on how it goes !!

Should it really be a ford part I have read a lot about the focus not really likeing pattern parts ? Also would this if it is the filter only give me problems when warm and at idle and not any other time ? Sorry lots of questions just as you see it's a 1999 and don't want to keep spending and spending lol it's a brill car other than this issue all panels are still straight paintwork and interior above average for age don't really wanna have to get rid of it over something that will probably be simple but do have to draw a line at some point

fuel filter aftermarket, as long as you dont buy a bog cheap one, then you should be fine!

I would advise if its not too expensive, buy a ford part though!

No worries cheers !

Bought and fitted fuel filter this morning from fords idle still same. How ever decided to unplug tps with engine running on tick over I did this when car was warm and starting to idle bounce and when I did it returned to normal ! Plugged it back on car returned to rough idle do I assume this is my fault ?? I must have a dodgy one if it is as I have replaced this already but was not from ford just a motor factors wot do u recon guys ?

Try gapping the plugs down to 0.8mm - they are often pre-set at 1.0mm, the narrower gap may help the tickover, and help the spark stay in the right place/ help protect the leads/ coil packs

Irridium plugs are best, (last longer/ less liable to foul) i prefer NGKs but try other "premium" makes

1100rpm is very low for a small petrol-engine that revs to 6k, to put it in perspective, when i 1st got it my Mondeo TDDI 2.0 was "gutless" below 2k, and only revved to 3.5k, (i had to keep it between 2000 and 3500 rpm to make progress)

- ie - just keep it above 1100rpm when you drive it

If you need something that pulls from tickover - get a tractor (or some diesels)

Here is the dyno printout - it does not even start 'till 1k -

http://www.mybluefin.co.uk/curves/focus16.pdf

(the remap would help it pull better from low revs)

I done the gaps when I first put the plugs in found yesterday that the tps I purchased is faulty soon as I unplugged it whilst running all returned to normal . Its not my car it's my other halfs I have an e39 m5 she is learning to drive and its causing her a problem as she is at low speed most of the time which is when the issue is happening . I think if this don't solve it I will swap for a tractor as more reliable than a ford at this point also lol