Ford Cougar (1998 - 2000) - 99 2.5 Low rev misfire - high rev battery light !

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Sun 3 Aug 2008 09:31
99 2.5 Low rev misfire - high rev battery light ! - markeastwood
I have recently bought the car and it came with a misfire at low revs. The car stutters on hard acceleration up to 3,200 (where the extra ports open) before clearing. The car then drives fine up to about 5,000 when the battery light comes on.

There are no fault codes logged in the ecu.
Anyone got any ideas before I spend any more cash swapping out the battery?

Edited by Pugugly on 03/08/2008 at 13:34

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Sun 3 Aug 2008 09:42
99 2.5 Low rev engine misfire - high rev battery l - caine
Not sugesting it's same,but I had a vauxhall in once that had a whole raft of wierd symptoms that turned out to be a intermitently faulty alternator,scaling up to 18.5 volts at some points.totally confusing the ecu.no fault codes.worth checking alternator output voltages through the rev range.no cost test.cant hurt.
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Sun 3 Aug 2008 12:31
99 2.5 Low rev engine misfire - high rev battery l - markeastwood
Thanks Caine

There's a steady 14.5v throughout the rev range. This drops to 13v under hard acceleration. I think the alternator is on the way out, but I can't tell if it's causing the misfire as it only happens under load and once the engine has warmed up.

I'll try plugging my laptop in this afternoon. I'll take it for a drive and watch those volts.
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Sun 3 Aug 2008 12:46
99 2.5 Low rev engine misfire - high rev battery l - elekie&a/c doctor
Usual causes of missfire on these are plus,leads or coil pack.I can,t see the alternator problem being related to this fault,however may be a good idea to check the wiring to the rear of the alternator as it is common for the wiring to overheat and burn up the terminal posts.hth
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Sun 3 Aug 2008 19:16
99 2.5 Low rev engine misfire - high rev battery l - markeastwood
Good one guys.

Swapping the plugs did the trick.
Looks like the (dis)service the garage did before I picked the car up caused the problem. The gaps on the old plugs were much wider.

Thanks for the help.
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