i was coming back from work on monday, doin 70mph (ish) on the a34 with my foot down on the accelerator pedal when all of asudden my car started decelerating. then it picked up again, then decelerating again in a kind of stop-start fashion. it felt like i was running out of fuel (that feeling you get if you proper red line it) but i had quarter of a tank. luckily i was passing a junction so i got off and put £20 quid in the tank - just in case. i managed to get home after but the car didnt feel like it was giving me everything its got - it felt lile it was holding back. felt like this all week untill yesterday - i got off the a34, through didcot and had to wait at a roundabout. as i put my foot down to go i had no revs, then i got a few, then none (ie the same thing that happend on the dual carriageway monday). luckliy the roundabout is 10 seconds from my house so i chugged home and parked up. i sat revving it and i was putting my foot right down and was only getting 1500 revs or so, then a bit more, in a kind of spitting fashion. i killed the ignition and restarted the car and it was ok, i was able to rev up to 5000.

 

so, any ideas? a couple of people have said the fuel filter??

Had the same problem on my gti, turned out it was the MAS. Fitted a replacement and it was ok ever since.

But could be a number of things, but that was my experience. Also see if there is any leaks on the hoses.

unplug the MAF sensor and see how it runs (the flat plug that plugs into the intake just after the airbox). also if it felt like it was running out of petrol it could be a blocked filter,. fit a new one just in case and that'll rule it out.

could be the cat as my mate had a similiar thing happen when his went

some more on this problem. still doing above, i put my foot down to go but no revs. im finding if i rev it in neutral its spitty and garguly and doesnt rev above 1-1.5k. im also getting the battery light come on.

 

any more ideas on this problem guys? so far ive done:

 

maf sensor

lambda sensor

spark plugs

leads

throttle body gasket

fule filter

ive had the fuel tank off and inspected it for rust - fine

fixed hole in fuel breather pipe

coil pack

 

done all of these and still car playing up - spent a fcuking fortune so far for didly squat.

 

i took it to the garage the other day and the mechanic felt wires getting hot. he separated them and found which one it was and traced it back to the ecu temp sensor. at the multi plug that plugged in it was melted together so were lookin gat that at the moment.

 

any ideas of what to try next if it isnt this? im thinking the crank sensor?

Edited September 15, 200816 yr by dreadscort

injector hoses/fuel rail?

check the cables going to your alternator and your starter motor...

Edited September 15, 200816 yr by Super_Scort

ecu temp sensor.

probably crank sensor

Sounds exactly what is happening to me although i can rev it to redline fine in neutral (when the problem occurs) which i think rules out my cat. Next thing suggested to me by people on here was ecu pin checking so when i get round to it i can tell you if i find anything. Wont be in the next few days though since i only own broken things and not enough time to eat let alone sort everything out.

 

When the car perks up again, do you feel a slight jerk (i mean slight) and then it picks up like it should do? As in, the power is either on or off. On mine, it feels like its misfiring constantly whilst the problem is there and then smooth again when it goes. Im thinking that the ecu is cocking up the fueling but why it comes on and off i dont know.