I have never come accross this before on a duratec or zetec for that matter, my mate just bought a really nice st170 and noticed it on the drive home, its drives and pulls well through the gears but when changing up under load he gets pinking until it reaches 2500 revs, I could only suggest using higher octaine fuel, plugs, leads and coil pack, he has in the last week changed the lot and his one still does it, any ideas on where I can tell him to go next as I was thinking the AFM

 

Is it making a noise? The ST170 i known for a flat spot in the rev range around 2500k. Can be sorted with a remap though.

 

Mines got a flat spot at 2500 but if I run it on super it's fine. Didn't have it when I first bought it just started one day

 

the only fault he has is pinking which fades out as he goes through the revs, never seen this before on one of these engines, in the old days it was a timing issue but on these engines its pre set with no alteration

 

Hi,
I cant help with this problem of your mates, but my st has exactly the same problem. As you im at a loss as to what is causing it, the only thing i was going to try was to clean or replace the MAF sensor??

My st even pinks on the overrun!! Its an 03 and runs superbly otherwise..

Apologies, re-read your post again and noticed the MAF is on your list to do also.
Chris.

 

I own a ST myself so the plan is for him to try my maf etc and see if it cures it

 

Ok, be great if you post up the results, id love to know what causes the pinking on mine.

Chris.

 

if its done more than 60k change both lambdas for new genune ones

 

did this get sorted out? as mine is very simular to this and ive recently had EML on so im thinking Lambdas?

 

spoke to him yesterday and he says hes been saving to buy them as they were expensive, so once fitted I will update the thread

 

Nice one cheers mate