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  Its not fuel! cleveland still missing above 4000rpm.

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Author Topic:   Its not fuel! cleveland still missing above 4000rpm.
70coupe
Gearhead

Posts: 382
From: Toronto,Ontario,Canada
Registered: Aug 2000

posted 10-10-2002 07:38 PM     Click Here to See the Profile for 70coupe     Edit/Delete Message   Reply w/Quote
My fuel pressure seems to be fine but when the rpm reaches 4000rpm or so there is a small miss in the motor. I changed the plugs,wires and complete distributor as I have a spare. Still does it! I run msd,so I checked my grounds and they seem to be good. Any other ideas, I'm going to the track for the weekend tomorrow.
Brian

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351c 4v clsd heads
60'1.619
1/8 [email protected]
1/4 [email protected]

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kid vishus
Gearhead

Posts: 5248
From: middle of NC
Registered: Oct 2000

posted 10-10-2002 08:20 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
If it's a constant miss over 4000, and it just started happening, I would lean towards the valve springs going sour.

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denny
Journeyman

Posts: 65
From: Northfield NH USA
Registered: Jul 2000

posted 10-10-2002 10:39 PM     Click Here to See the Profile for denny   Click Here to Email denny     Edit/Delete Message   Reply w/Quote
I was thinking the same thing.

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D French
67 427 Fairlane(A/SA) 73 Mustang 351c

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MrWesson22
Gearhead

Posts: 1212
From: Dacula, GA
Registered: Sep 2000

posted 10-10-2002 11:18 PM     Click Here to See the Profile for MrWesson22   Click Here to Email MrWesson22     Edit/Delete Message   Reply w/Quote
It's a bad carb. Send me yours and I'll be kind enough to swap you mine even.

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Neal

69 Gulfstream Aqua Grande
351C/4sp

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Dusty Kiser
Gearhead

Posts: 127
From: Bethel,Oh USA
Registered: Mar 2002

posted 10-12-2002 03:59 PM     Click Here to See the Profile for Dusty Kiser   Click Here to Email Dusty Kiser     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by 70coupe:
My fuel pressure seems to be fine but when the rpm reaches 4000rpm or so there is a small miss in the motor. I changed the plugs,wires and complete distributor as I have a spare. Still does it! I run msd,so I checked my grounds and they seem to be good. Any other ideas, I'm going to the track for the weekend tomorrow.
Brian


I've probably missed previous info, but I assume you've already run a compression and/or leakdown test and all is good. You've read the plugs and they look good also? You don't specify if it misfires anytime it goes over 4G's or if it's only with no load while sitting in the garage. You might perform a cylinder balance test to see if it's a random miss or if one cylinder is the culprit. Can we assume you've thoroughly inspected the valve train and have no keepers pulling through or shims spit out? Could be a weak spring(s) as Kid says or lobe wiping off the cam. It's a process of elimination. A sharp guy with a scope could tell you what it needs pdq.

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N266fords
Gearhead

Posts: 1039
From: Spokane ,WA USA
Registered: Apr 2003

posted 07-22-2003 03:45 AM     Click Here to See the Profile for N266fords   Click Here to Email N266fords     Edit/Delete Message   Reply w/Quote
I dont know if you have found the problem but it could also be a weak ingnition like a coil bad wires.For example if you engine load rise with rpm that is then so does the demand on the electrical load to supply enough juice to light it off and burn it completly. I had a coil go bad once on me and It was a pita to figure out, it ran like a raped ape until 3500 rpms then if my foot was in the wot pos it would fall on its face like i ran out of fuel ,ease up the the gas pedal and it would turn 5500 with no problems at all. I checked the carb fuel presure line filter timing ect.Finaly just swaped the coil and zoom off I went. put the old one back on it back came the problem..Bruce

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