Chevy 350 tpi miss fire on light throttle

[Robbsc10]

Hi, hope some one out there can shed some light on my problem. I have a 350 tpi in my 63 Chevy truck, I have noticed my truck misses a bit on light throttle doing about 65 - 70 mph at around 1900 rpm. If I put my foot down a bit more it drives through it and drives ok.

I recently cleaned out my idle control valve and checked that my throttle position sensor was set up correctly but it still does it

Please if any one has any idea please let me know

Thanks
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[68c10airstream]

Hi to the uk, if the distributor is behind the waterpump a lot of issues with cap and rotor. I would go out at night where it is very dark, use a squirt bottle with water and mist the manifolds to get steam and mist plug wires and watch for sparks and listen for snapping. Replace what lights up, but don't touch or you may be dead. Good luck brian f.
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[oldspowered67C10]

disconnect the EGR and see if it goes away.

[68c10airstream]

Hi again, i should ask what trans? Possible lockup torque converter shudder that feels like a misfire. If an od trans lockup wired through your brake light switch, when misfiring, hold gas pedal steady and lightly touch the brake pedal just enough to light the brake lights without dragging the truck down. If the shudder/misfire is gone, possibly trans issues. Also, when you described this condition, you are asking more out of your coil (30-40 thousand volts) during tip-in on light loads during lower rpms. At idle you only need about 8 thousand volts. So the higher voltage demands the greater chance of misfire, especially voltage leakage to ground instead of firing the plug(s). Another member said disconnect egr, but timing advance go hand in hand with egr application. Egr disconnected equals pinging, spark knock, possible ignition retard, or holes in pistons. So be careful. Dirty injectors and intake valve carbon deposits can also give drivability issues. I clean my injectors yearly in my 68c10 with a 5.3 ls series engine and can tell the difference! I worked at dealerships for 30 plus years and dealt with a lot of drivability issues especially on gm truck line but didn't see many tpi's. That was many years ago.
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