VTS Misfire - Help!

30th January 2016, 23:04

Right everyone,

I have a 2003 Saxo VTS, and has an odd misfire/cough every few seconds, isn't too noticeable under load but you can notice it at idle or motorway cruising. I have tried another MAP sensor, coilpack, crank sensor, coolant temp sensor, changed the fuel filter, air filter and still no joy.

I have a feeling its running a bit rich too, can't get over 40mpg on a 55-60mph motorway run driving carefully. I've read 45mpg+ is entirely possible from a VTS on long runs.

It also seems to hold the revs a little, especially at around 3-4k if I lift off the throttle and dip the clutch, it'll stay at that rpm for a second or two

Anyone got any ideas?

Thanks

31st January 2016, 00:16

Quote:

Originally Posted by johnmclaren

Right everyone,

I have a 2003 Saxo VTS, and has an odd misfire/cough every few seconds, isn't too noticeable under load but you can notice it at idle or motorway cruising. I have tried another MAP sensor, coilpack, crank sensor, coolant temp sensor, changed the fuel filter, air filter and still no joy.

I have a feeling its running a bit rich too, can't get over 40mpg on a 55-60mph motorway run driving carefully. I've read 45mpg+ is entirely possible from a VTS on long runs.

It also seems to hold the revs a little, especially at around 3-4k if I lift off the throttle and dip the clutch, it'll stay at that rpm for a second or two

Anyone got any ideas?

Thanks

Upstream lambda sensor could be faulty. It would be worth fitting a good quality one. Downstream sensor doesn't matter so much. Either of the sensors failing could let the engine run rich and cause slight misfire.

My old 2001 GTi managed 45mpg going to FCS and back and that was driving at 70mph. 50mpg+ is entirely possible driving at 60mph.

As for your sticking revs, that could simply be the idle control valve. simply remove it and clean the housing the plunger goes into and clean the plunger itself. do NOT pull on the plunger, just wipe it clean. spray some WD40 before re-fitting too

1st February 2016, 20:53

Id look at lambda sensors go grab some off scrappers and see if that solves it. Or maybe look to doing something more such as a terraclean on it. And what Martin said above...

NO idea how many MPG I get depends on my driving if not tanking it down motorway then I can easily get 350 to 400 miles on 45 liters at 60 to 70mph on avrage.. so what ever that works out per gallon i duno lol