1997 GMC 1500 uphill misfire?

I have a 1997 1500 GMC, 5.7l. I keep getting this misfire at hire speeds... provided I'm going uphill of any sort. Itll usually start between 65 or 75 mph. If I floor it, it'll go away and accelerate fine until evevtually the SES light comes on. I've had the entire fuel system checked, from the injectors on back to the pump. Had pump replaced. Distributor checks out fine.b replaced coil, wires, plugs, cap and rotor. Also replaced fuel pump when it was going bad. I've finally been told either my catalytic converter is clogging up or its my tps. Help?

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  • Anonymous
    5 years ago

    I'd try a new set of plugs and install them very carefully. Start them by hand, no fumbling them in on a socket, use a piece of rubber hose. Sometimes they've been dropped before you buy them and get imperceptibly cracked.

    TPS has absolutely nothing to do with it.

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