okay, I have a 52 plate ST170 which has a kinda surging feel to it when doing any steady speeds ie 40mph in 4th gear or just generally holding a constant speed, also feels sluggish low down in the revs like its hesitatant to go.

I've changed the plugs, leads, coil pack, fuel filter, alterantor (was faulty anyway) and have yet to cure it, ive also had it checked at my local garage on the diagnostics plug and that threw up no faults or error codes.

Not sure what to check for next, can any one shed any light on the matter or have experianced simular ?

 

I also have the "surging feel" you mention in my 02 plate car. The sluggishness is only when it's cold on mine tho. According to t'internet, the surging is due to a failing EGR valve, but my understanding is that there isn't one fitted at all!

 

First check is the MAF. Unplug the MAF and see if the problem goes away. If it does clean the inside of the MAF with carb cleaner and plug it back in.

 

hiya

i have an st170, and apparantly in some of the forums out there they say its a known thing with the map of the ecu rather than an actual misfire

if ya get a blue fin or a remap it smooths the problem out

dave

 

Alex, it is a lot more noticable when the car is cold as you say, and as above I have to heard of the difference in the ECU's from the earlier cars to the later cars (03 and above having an updated map).

I've tried the MAF unpluged and think it had cleared the issue, although only short road test, will find out tomorrow for sure.

Thanks for the replies