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        General >> Problems >> hesitation/misfire under light throttle
        
(Message started by: nigelt on May 10^th, 2005, 1:18pm)

Title: hesitation/misfire under light throttle
Post by nigelt on May 10^th, 2005, 1:18pm

Hi Guys,

I have been looking on this site for some time now with great interest as it seems to have the most comprehensive information regarding the workings of the engine management systems etc. However, I am being somewhat cheeky here as I don't actually own a scorpio, but another of those Ford cars..... a Mondeo.. I know I Know... but someone has to...

I hope you may still be able to help me though... as the systems seem very similar. As above I have this problem at light throttle that was not there before and its spoils a good drive. I bought an ELM320 with software to look at the system and discovered a couple of issues. one was that after driving for about 12 mile @ 70+ the system would go into 'open loop fault' and then when slowing down and driving at near clossed throttle I would get this missfire/jerking. I changed the O2 sensor and this seems a lot better. But I still have the hesitation/misfire at other times at light throttle. I notice that at idle the LTFT figure is at 16-17% which seems rather high to me and wondered what you guys get on a scorpio. ( I understand there would be some difference here). I don't believe the EGR valve,solenoid,DPFE to be at fault here as I have tested them and the all seem ok. so I'm thinking air leak but I'm damed if I can find one. Any suggestion would be most grateful...

Nige :)

Title: Re: hesitation/misfire under light throttle
Post by Octavian_P on May 10^th, 2005, 7:34pm

i've got something similar, a hesitation, a delay in throttle. If i accelerate hard and fast, it kind of misfires and then revs up but after a delay.

i've cleand the maf, it's connector, changed air filter, lookd at ignition coils, spark plugs, all seem ok. Didn't figured out what's wrong

Title: Re: hesitation/misfire under light throttle
Post by bigmaltwo on May 11^th, 2005, 2:35am

please check wiring to coil packs :o
as i only found out myself yesterday, the flaming insulation cracks and causes misfire! >:( >:(
started as a slight misfire on over-run and got gradually worse, n worse, n worse etc etc etc :-[
thought it was going to be yet another (expensive of course) pain in the *@@*, but was chuffed to @**@ when i sussed it!
good luck.
mal.