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Topic: Engine erratic at around 40-50mph (Read 479 times) |
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Fidget
Junior Member
Vox et praeterea nihil
 
Posts: 76
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Engine erratic at around 40-50mph
« on: May 23rd, 2007, 9:31am » |
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I have a feeling this may be a fueling issue (such as the fuel pressure regulator) but I'd be so grateful for any advice on this ...
My 2.0 16V is lurching/dropping back when cruising at between approx 40 to 50mph. By this I mean that if I hold the accelerator at a single position around these speeds, the car seems to lurch forward slightly, then drop back again (as if I was accelerating then decelerating).
I haven't had the chance to run a scan yet, but hope to today or tomorrow.
comments much appreciated, tyvvm
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Matt.
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Jonnycab
Senior Member
Former owner of 2.3 Ultima Facelift saloon
Posts: 3900
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Re: Engine erratic at around 40-50mph
« Reply #1 on: May 23rd, 2007, 10:38am » |
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Could be a coil pack problem, especially if it's only happening under a certain load 
Not sure the fuel pressure regulator would cause these symptoms as it is under a constant pressure from the fuel pump & if it were faulty, then it would cause problems across the whole driving range....I think 
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Simmo
Administrator
I'm an OAP !
Posts: 5508
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Re: Engine erratic at around 40-50mph
« Reply #2 on: May 23rd, 2007, 11:31am » |
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Fidget, before you do anything else have a read of THIS and clean the MAF.
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Now I'm an OAP
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Engine erratic at around 40-50mph
« Reply #3 on: May 23rd, 2007, 11:43am » |
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Hi Simmo, I thought of the MAF and have already replaced it with a new one - result is no difference.
Jonnycab, I did replace one coil pack a few months ago, perhaps I should try replacing the other with the same. I was racking my brains to see if anything in a scan would reveal a faulty coil pack, but can't think of anything.
thanks for the help guys.
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Matt.
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Octavian_P
Senior Member
 
Posts: 1126
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Re: Engine erratic at around 40-50mph
« Reply #4 on: May 23rd, 2007, 11:55am » |
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Try to disable the over-drive. If the MAF is dirty the car starts to hunt for higher gear.
Later edit: wow the same responses in such short time
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2.0 16V Ultima|2.3 16V Ghia|2.9 24V Cosworth Ghia
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Engine erratic at around 40-50mph
« Reply #5 on: May 23rd, 2007, 12:02pm » |
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We're all on an early lunch, 
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Matt.
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TiberiuS
Senior Member
Ex. 1996 2.3 Ultima - RIP P789 KHJ
Posts: 2257
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Re: Engine erratic at around 40-50mph
« Reply #6 on: May 23rd, 2007, 4:04pm » |
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Hi. The one that I always say but what does the loom look like where it snakes around the back of the engine to the coilpacks?
Sounds like a misfire issue, I'm getting similar part throttle hesitation on the Jag but it's more subtle, more like a power loss - maybe because each plug has it's own coil as opposed to 2 sharing on the DOHC Scorp
That's the bummer, scan wouldn't show anything unless it triggered a misfire code and then I presume the engine would be in limp home mode anyway.
I hope Jonny's right about it causing this symptom, would make my day to lose that hesitation 
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Bruce - '07 Jaguar XKR coupe, '95 Jaguar XJ Sport 4.0, '82 Ford Capri 2.0 Ghia, '15 Honda Civic (sloooooww..)
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tintin
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I'm a YaBB newbie!
Posts: 592
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Re: Engine erratic at around 40-50mph
« Reply #7 on: May 23rd, 2007, 5:03pm » |
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yep, worth a scan, also look for a blocked cat, might produce similar symptoms.....
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'95 Cosworth Ultima
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Fidget
Junior Member
Vox et praeterea nihil
Posts: 76
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Re: Engine erratic at around 40-50mph
« Reply #8 on: May 23rd, 2007, 7:11pm » |
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Thanks guys,
The cabling was replaced (cut back to good and new cable soldered in a couple of months ago), that's not to say that a new loom is not on the cards (ford parts uk still do them).
The CAT was replaced December last year, no noises from it, so I believe its ok.
I think I'll have to go with replacing the other coil pack and the fuel cut off loom. If that doesn't solve it then I'll have to spend a day with her.
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Matt.
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hellblue
Full Member
Ill have silver,it dries just as fast !
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Re: Engine erratic at around 40-50mph
« Reply #9 on: May 23rd, 2007, 8:45pm » |
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Dont over look the EGR this may cause this too,remove vac. hose from egr valve & plug it & go for a drive,it will be ok to run with it blocked off, also remove the egr valve & clean it & make sure it sits on its seat, ie shut.
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Gary
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