2001 Ford F150 Hesitates, without throwing codes

2001 FORD F-150
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CAMF150
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Engine Performance problem
2001 Ford F150 V8 Two Wheel Drive Automatic

My truck runs good for a few miles but after that it runs sluggish like I am pulling a huge load. New plugs new cats and muffler new, throttle position sensor, new belt, Cold air intake. Not throwing any codes. I run 93 octane and ran fuel treatment. some days it runs fine all day and others its horrible. Its actually Idling little High now. It eventually comes back down to 600 but kinda hangs around 1000 when sitting still. Idles smooth tho and always starts fine. gets good fuel economy also. 99k miles. Please help. I am very frustrated. My truck has always ran fine until I changed the plugs. Ford motorcraft plugs and they are gapped .54. No leaks anywhere.
Aug 17, 2009 at 6:07 PM
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MHPAUTOS
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Hi there, did you actually run a scan? as not all faults will bring up the check light, have you tried new plugs again?

Mark (mhpautos)
Aug 17, 2009 at 6:11 PM
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WINEBURGER
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have you replaced the fuel filter
Aug 17, 2009 at 6:12 PM
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CAMF150
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Yes we ran a scan and it passed with no codes. the plugs are new motorcraft platnium and I did pull them and recheck the gaps. I also replaced the fuel filter last week. It acts like an old holley carberator that the secondarys wont open up on.
Aug 17, 2009 at 6:16 PM
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MHPAUTOS
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Air filter not blocked? fuel pressure ok? if no codes it will be something not controlled by the ecu, re check all the basics, don't presume that something is ok, check and make sure.

Mark
Aug 17, 2009 at 6:21 PM
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CAMF150
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Air filter is new , afe cold air intake. Fuel pressure was checked to be ok. If i drop it into first and hammer the throttle it will run. but with it in drive it seems like it shifts early and bogs down. Thats why I replaced the tps today. but it runs the same.
Aug 17, 2009 at 6:25 PM
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MHPAUTOS
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I wonder if this may be a transmission issue? have you checked the oil level & condition?

Mark
Aug 17, 2009 at 6:36 PM
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CAMF150
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We had the trans rebuilt a year ago. the fluid is full and clean. I do pull a trailer with it but it did really good this past week for a few days then started acting up again. Is this a linkage issue? Although it all seems fine and normal to me. This is a very strange issue I am having. This truck has ran great until now.
Aug 17, 2009 at 6:45 PM
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MHPAUTOS
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I would go get the trans checked by a specialist lest just rule that out,

mark
Aug 17, 2009 at 10:49 PM