flat spot and missing

[xr6'n]

hey guys, just having trouble with a flat spot and now a miss with my series 2. when the throttle opens up it has a dead spot till about 3000 revs and some times misses and makes a funny noise back through the air box like the timing isn't advancing and is to retarded. i checked the timing myself and it seems to be fine the funny thing is it doesn't do it all the time and does it more when the weather is cold. sum days it has heaps of power and then hardly any. any suggestions or help would be appreciated?

[bodes-sh]

have you replaced basic stuff like plugs, leads, etc? if you haven't try that, also i'll say it before JC this time, check your fuel pump too

[xr6'n]

replaced all leads and plugs, timing fuel pressure. the last thing that i can think of to try is maybe a throttle position sensor? cause, (correct me if im wrong) if that doesnt work properly it will rely on the maf sensor?

[bodes-sh]

not on a 6, they have a map sensor....you could try cleaning the tps wiring plug, and also cleaning the map sensor, to do that you have to remove the throttle body

[xr6'n]

just cleaned the throttle body, and it was really dirty, the car is running a lot smoother with the gear changes and has lost the flat spot, but is still missing in the lower rev range. im now stumped on what it could be. might have to take it in and get the diagnostic computer put on it, any other surgestions would be great

[FGII-XR6]

have you tried the O2 sensor?

[bodes-sh]

^^i don't think that the o2 sensor is going to cause a miss....try replacing the coil pack and running some injector cleaner thru it, or getting the injectors removed and cleaned

[Tickford Kid]

Start with the spark plugs, then go leads and then coils.
Good luck!!

[xr6'n]

its booked in frinday morning to go on the dyno and the diagnostics computer, i have money on it being the throttle position sensor

[JC]

I have money on it being spark or fuel ralted, not TPS. As bodes said, fuel pump check would be worthwhile, as would rechecking all plus, leads, and coilpack for signs of wear/failure.

[xr6'n]

it only misses under load at low revs which makes me think it not a fuel pressure. from a standing start feels like the car has about 60rwkw rite up to the limiter. but with a rolling start from bout 50km/h feels like it has 100rwkw. (this is example only). and after u take your foot off in drive it sumtimes over changes to a to higher gear. which is why im leaning to wards the throttle sensor.

[Burley]

this has got me stuffed??? i know nothing about this....but would the car still go if the fuel pump was gone? im thinking of replacing this but i dont know if it will be pointless

[bodes-sh]

yes the car sill run if it's on it's way out, i know mine is, and i'm tossing up whether to just get a walbro or similar or a standard one

[ForteAU]

my AUII isnt missing but it is very sluggish like it is a tired old ex taxi but it only has 112 tho on it, i have had a pcm upgrade, new plugs, cleaned tb, tps checked, no other error codes. the main time it is sluggish is from a standing start till i hit around 3 1/2 - 4k revs then it goes much better. any ideas, suggestions?

[Burley]

just had fuel pressure test on my car....few error codes came up in diagnoses....map fault....dunno if they are old or new codes....will see in few weeks...but my fuel pump is fine...mate from ford thinks it could just be injectors

[xr6'n]

well they found sum of the problem number 5 spark plug lead was arcking out on the head, and they were brand new. 2 set of faulty leads so i put a different brand on and it made a huge difference in smoothness, its still not right though, got the flat spot back and still a hesitation miss if i put my foot down.

has anyone had any problems will a particular brand of spark plugs?