86 S-10 holding back

I rebuilt my 1986 S-10 Blazer 4x4(2.8L TBI.A/T.) No error codes, starts every time, purrs like a kitten. Takes off w/ok speed then in 2nd & 3rd feels like i'm pulling a house. I have to hold down the throttle to
maintain speed on inclines which causes overheating. Slows to 25 mph on bigger hills. on level ground it travels ok. w/nt climb to highway speed. Seems to be using a lot of fuel. dealer test only ckd engine @ idle. of course no problems found. STUMPED. PLZ HELP.
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Disconnect the cat or remove the o2 sensor to check for a clogged cat.

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Check the adjustment on your throttle valve cable. Could be tossing it into top gear (and possibly locking up the TCC) too early.
Make sure you check your timing (with the ALDL port grounded, or the EST plug unhooked) also.

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I checked the above. Timing perfect,tcc ok. still holding back. w/minimal throttle it travels okay. As you need more power, it starts holding back instead of picking up normally. full throttle still feels labored. the noise is there, but not the speed. I'm just this close to having a chevy bonfire.
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s10freak wrote:

Try Getting rid of the AC SPARK PLUGS.
When I had Chevy Wreckers The AC BRAND Spark plugs Cut The Trucks Torque ( POWER) WAY Down !

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The change in plugs made a world of difference. I still have some power issues, but I can now drive the vehicle w/o worry of going too slow. Thanks. John.
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In article

Does this happen also when sitting in park or neutral? Reason I'm asking is there may be an exhaust restriction (converter plugged, etc).
Keith
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the exhaust consists of the headers, to one pipe to turbo thrush muffler and tail pipe out the side b4 rear tire. Eliminated the converter.I am using AC plugs. Will try a new plug this wknd. Recommendation on plugs? I also have an MSD Ignition system. Might this have an affect? I really do appreciate all your help. My troubleshooting knowledge is increasing w/ea feedback. Thank you.
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