96 gmc 1500 v6 vortec bucks at highway cruise speed

GMC C1500
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DAYZOFF
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200,000 km/ 120,000 miles
Truck starts fine and idles good, maybe some slight missing until it warms up. The most noticeable problem is at cruise speed on the highway the engine bucks with slight pressure to fuel pedal. If I press down on pedal lots of power and runs great. So basically I would say it idles great with lots of power during acceleration and at a nice cruise it runs annoyingly lousy (bucks and hesitates) with no trouble codes present. New plugs wires cap rotor fuel filter last winter ran great til 1 month ago. Today was a first, truck sat for a couple days and went to start it and just rolled over no go, finally got it going seemed to have flooded itself out and still no service engine light on yet. I have been searching high and low for possibilities bought a scanner and fuel pressure tester.
Nov 13, 2007 at 12:58 PM
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RASMATAZ
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Inspect and test the coolant temperature,oxygen, and throttle position sensors-to include the EGR operation/carbon in it.

What's the fuel pressure KOEO and KOER?
Nov 13, 2007 at 2:44 PM
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DAYZOFF
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Key turned on pump hums and quits at 62 psi, then started engine pump holds at 58 psi. These are apparently right in the proper operating ranges I believe.
Nov 13, 2007 at 6:07 PM
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DAYZOFF
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OK maybe onto something, tested a couple sensors and checked out ok. I unplugged the tps started it up and noticed it ran better right away, went for a ride and seems to be fixed other then it shifts harder probably because its in limp mode but going to change tps tomorrow. Will post back results.
Nov 14, 2007 at 8:22 PM
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DAYZOFF
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Replaced TPS and truck runs great again finally.
Nov 16, 2007 at 11:56 AM