I've had my 2004 ST170 for 2 years now, and I love it to bits...which is quite wierd since I've owned my 2007 Wolf ST3 ASBO for over 5 years...and really prefer to drive the 170 on a daily basis.
...But there's a problem I just can't get my head around.
The engine performs perfectly (with the usual intermittant hesitation when accelerating through 1500 - 2000rpm), as expected with Ford, all the way up to 6000rpm...as long as I stay in 4th. As soon as I select 5th/6th, I get a misfire around 70mph, and insufficient power to accelerate. Like I said, if I drop to 4th & boot it, everything is fine...all the way up to 6000rpm.
It's running fully synthetic 5w30, changed in early November.
I also changed the plugs, as a matter of course...but there was no change.

Can anybody shine any light on this?
Maybe a swirl flap, cam timing issue???

Thanks in advance

 

may be a coil pack as I have had this happen on other 170s, clean the plugs check HTs etc, doubtfull its timing unless you get pinking, VVT is meant to be changed every 60k

 

I put a Lucas coil pack on mine recently. Was fine for a month then started with the same symptom's your having. Swapped it over with my other 170's mototcraft jobbie and all is fine again.

Screw you Lucas

 

I would say coil pack too.

 

Buy msd coil pack kit from pumaspeed fits straight on even thou it's an early zetec pack comes with new leads etc
Bargain really as ford don't sell the leads as a set anymore so you buy them separate and all 4 was around Ł80 robbing bastards
It's the uprated blaster coil pack

Hope this helps

 

only issue with the MSD coil pack is the heart attack from the price lol