Hi all.

I have a 53 plate st170 that has now covered 78k.

All has been well but of late noticed it's abit lumpy on idle, but clears if i raise the rpm slighty.

I also notice at 2500 rpm it feels if it's slighty holding back underway, but again if you put your foot down it clears.

Any idea's?????

Thanks

Dan

 

Can't comment on the lumpy idle, but mine definately doesnt like 2.5k either. Burps, farts, stutters and generally tells me to get away from that rpm, particularly on a constant throttle.
Don't drive at 2500rpm

 

Its usually the fuel pump in the tank thats at fault when it hesitates at 2500rpm. Do you find it normally does it when the fuel is nder 1/4 tank? Id probably say its going to be lambda sensor causing lumpy idle etc,common on these

 

try cleaning the throttle body out over the years they cake up with soot and start to stick untill you put your foot down. will take you no longer than 30 mins max to do the job