AU3 SR not performing..

sneaky · 03-04-2007, 02:51 PM

hello guys and girls..

just a quick and hopefully straightforward question for you peoples.

The mighty coon is not running properly. it has bugger all power low in the rev range, and when using a heavy foot the car coughs and splutters to about 3500rpm - 4000rpm, then accelerates as it should.

as i said its an AU3 SR, 6cyl auto with 135k's on it and a finer filter foam air cleaner (only 'mod')

i thought it might have been dodgy fuel (put $30 in 2 weeks ago from a servo i don't normally go to) however, it has since had 2 full tanks put through it, the latest being vortex 98 with wynns fuel cleaner stuff as well. and it still runs crap.

it does seem to be ok when driven normally, just accelerating hard, or from 60k's to 100k's..

any ideas? its going for a service tomorrow so i'll tell the mechanic to have a looksee at it.

any chance it is plugs and leads?

cheers
-tim

b2tf · 03-04-2007, 02:56 PM

fuel filter

sneaky · 03-04-2007, 03:15 PM

cheers, it was changed not that long ago. i was also thinking it could be the cause, but its only 40,000k's old.

when should plugs and leads be changed? couldn't find it in the ford book

b2tf · 03-04-2007, 03:18 PM

it wouldnt hurt to do the plugs and leads, i think ford state every 100,000 or so but i find it more on a "do it when they need to be done" basis.

sneaky · 03-04-2007, 03:29 PM

might do the plugs and leads then, not sure if they have ever been done.

JC · 03-04-2007, 07:00 PM

I would say leads - had similar symptoms in mine, and it turned out that number 6 lead was pretty well snapped at the sparkplug.

Exact symptoms in mine were car ran fine at low throttle, but coughed and misfired at ***. A set of leads is only around $60, so cheap enough t replace. They really should be done every 2 years as a regular maintenance item. Sparkplugs only need replacing every 50,000km, so I reckon leads is the cause.

Could also be blocked injectors, but leads are easier to change.

If you want to check if it's leads first, just take one off at a time (I'd start with number 6) and give the car a rev, and see what it does. Plug that one back in, and then take the next one off (so you are running 5 cylinders each time). Make sure you turn the car off before touching the leads though - they give a nasty jolt if you grab them with the engine running (around 20000 volts worth). If taking a particular lead off gives the same misfire as with all leads on, then you've found your faulty lead.

If taking the leads off doesn't make any difference, then I'd suspect coil pack to be the issue.

AUTickford · 04-04-2007, 02:20 PM

If the filter is over oiled there could be oil on the maf sensor,havent heard of it happening on a ford but it happened to my mates wrx.Something else to try anyway good luck. :sm_headba

sneaky · 04-04-2007, 04:43 PM

went to get car back this arvo, fuel filter was cactus, full of crap. this is after 40,000k's - not the 90k's ford recommend...

i still think the hesitation is there, so for $60 it wouldn't hurt to change the leads, plugs are due soon anyway, may as well fix at same time..

**Mechan1k** · 05-04-2007, 08:49 AM

Doesn't matter what Ford recommend .. it's the crap the oil companies put in the fuel .... might also be crap in teh bottom of your tank .... best bet is to not let the tank get below 1/4 ... as there is more likelihood of pulling that crap from the bottom of your tank and through the filter (clogging it up)

mik · 05-04-2007, 08:24 PM

might be time to find a better servo?

sneaky · 09-04-2007, 08:08 AM

well i got the car back after 2 days..

fuel filter was dead, injectors were full of crap, spark plugs melted, 1 lead broken (wish they didn't replace it, i was going to get some 'fast' one's), and the idle control sensor is dead (has to go back next week to replace).

me thinks this is going to be an expensive service

and the mechanics / auto electrician said that the ford computers can 'learn' their way around faults. so the problems with the car could have been there from before i bought it and the computer has just dealt with it, but as soon as the battery was disconnected the computer went back to its original settings and wouldn't run properly.

oh well, as long as it goes better now.

RG · 09-04-2007, 08:18 AM

Just make sure that you change the fuel filter again in about 5k time in case there is still some rubbish in the tank.

JC · 09-04-2007, 01:23 PM

Quote:

Originally Posted by sneakypete23

well i got the car back after 2 days..

fuel filter was dead, injectors were full of crap, spark plugs melted, 1 lead broken (wish they didn't replace it, i was going to get some 'fast' one's), and the idle control sensor is dead (has to go back next week to replace).

me thinks this is going to be an expensive service

and the mechanics / auto electrician said that the ford computers can 'learn' their way around faults. so the problems with the car could have been there from before i bought it and the computer has just dealt with it, but as soon as the battery was disconnected the computer went back to its original settings and wouldn't run properly.

oh well, as long as it goes better now.

I've been told the same thing. You may get a half dozen errors before the ECU can't cope.