Hi there everyone im new to the site and was hoping someone else has had this fault im having and have sorted it and could give me a little advice.
yesterday I bought a 2002 st170 and it has covered 65k with full ford s/h and when engine is cold or hot I get a lot of flat spots all the time so if driving at 30 in 3rd and put power down it jerks a bit then clears but even driving at 30 and lightly pressing the pedal it still do it ,its as if its not getting a clear amount of fuel , realy bugging me as the car is amazing and don't wanna have to get rid just want to get a fix so I can enjoy the car ,any help would be good cheers

 

Try putting some super unleaded and see how it runs then. Mine used to do this and it was down to the fuel pump but if I ran it on super it was fine

 

ill give that's ago running on super but ive just filled it up with norm unleaded as it was empty but will try doing the super as soon as this has run out, How hard is it to fit a fuel pump, ive just removed the cheap air filter that was fitted and refitted the standered box but if I rev it it does a small pop or stutter if you get me ,do you recon it could be plugs and leads or coilpack ,its been fully serviced by ford since day one and its not due a sevice for another 3k I think

 

Ok done a good long run in the car today and it ran amazing and we was on a full tank and done 100 miles and now just between the full and 3/4 so its realy good on petrol to what I told it was going to be and the power is there ok its not the fastest thing on earth but the condtion of it and looks you get you don't need the speed but I am going to put a better exhaust on as just want that little bit more sound but as for the flat spots there still there driving under 30mph but are a lot better now its had a good run up the a12 lol but think im going to change plugs and leads and coilpack just incase and there not to bad for the cost and car is worth it lol

 

mine gets a bit of a flat spot at around 2 - 3k. its going to be remapped after i have a few other things sorted and ive been told that will remove the flat spots and make the car a much nicer drive. mine will be remapped on super unleaded too

 

I had the same problem and it turned out 2 be the fuel rail pressure sensor but u ca nt uy it seperately u need 2 buy the whole fuel rail.Ford where looking £246+vat no way wqs i paying that so i checked breakers and got 1 from the ford center for £50 &£9 delivery and it worked spot on.Hope this helps.

 

ive had real probs with mine today its started running lumpy on tick over and if at low speed its very jerky again ,does anyone think it would be a good idea to replace coil pack and leads plugs as everyone says the coil packs do go bad on these, help I don't have a lot of money and realy hope this is the fault ,when over 4k it drives amazing and pulls well but anything under 4k then it drives realy lumpy

 

Try putting £20 of super in it when the light comes on and see if it runs better. Mine ran loads better on super unleaded due to the fuel pump on it although after reading the post above could of been the pressure regulator but it was down to the fuel anyway. Easy way to test to see if it is fuel related, if it makes no difference you've not lost anything then look into the spark side. Its possible it could be the coil or leads breaking down under load but it might also of had cheap or the wrong plugs put in and not the ones for the ST but if it was me I'd try super first as you have to put petrol in anyway.

 

How did you find out it was the fuel rail pressure sensor in the end ,did it bring up a fault code ect

 

yea I will try that but its running rough on idle now like its running on 3 ,so would say its the leads or coil pack as ive had a look at the plugs and it says platinum on them and they look like a standered plug ,would you have a photo of one that it should have

 

ok just been for a drive and let it warm up first and it sounds little rough as if its only running on 3 cylinders but I could be wrong but if you drive it slow its ok but if your driving at 30 if does feel jerky and rough and if you floor it in 3rd at 30 its very hesitant but then clears and goes ,any ideas as I don't know if its safe to drive as don't wanna do any damage to the engine

 

I put in super unleaded in mine when the light went on also left it in2 ford 4 a full service.It still ran bad at low revs so took it back and they pluged it in for £75 thanks ford!anyway they told me it was showing up say fuel rail pressure sensor so i thought it would be like the oxegen sensor bout £50 but no ford looking £246+vat.Try the ford center its a ford dismantiler thats where i got the fuel rail for £50+£9 delivery cannt beat that.
Hope that helps Daniel Penn

 

Did u get ur problem sorted Daniel? Let us know how u get on.

 

Hi there no engine went bang so took it back to the dealer and said either give me my money back or well not gonna say what I said but he would of been having a big insurance claim lol , but ive now just bought a 53 plate one which is the same as the last one but it drives spot on but has eml light on but not affecting the car in anyways and passed the mot with it on but was an advisery tho but couldent fail it as not affecting the car so im going to get it read later today to see what the light in on for and sort it out soon as I know what to sort lol

 

Hope u have better luck with this 1.Did u find the problem of the light

 

Not yet mate im going to have the codes read tomoz and see what it comes up with as its not affecting the car in any way and it passed the mot with it so don't think it going to be anything bad to be honest but we will see