Back Fire, Non-ign. 'miss'

[KENNHON]

I have had NO problems with this beauty [Crew cab duallie] since new in '96... it now has 130,000 miles.... vacuum is showing 17 inches-is this low?but, it's steady. Fuel press. is 40 psi-my book says it should be 60 psi.... the pump was replaced 10,000 miles ago[ a premium Carter]. the EGR valve has 5 volts supply, and the valve has no open circuits. EGR plunger works fine off car; spring is fine.

 

The problem is that at 50 mph, there is a 'backfire',or 'hick-up', feels like a NON-ign. 'miss'. When any throttle is given, the 'hick-up' goes away. It idles fine, gas mileage is ok on highway 13-14 mpg at 70. plugs are new. wires are new. no wobble in distributor shaft.

 

Any help would surely be appreciated!!!!!!!!!!!!!

[KENNHON]

I have had NO problems with this beauty [Crew cab duallie] since new in '96... it now has 130,000 miles.... vacuum is showing 17 inches-is this low?but, it's steady. Fuel press. is 40 psi-my book says it should be 60 psi.... the pump was replaced 10,000 miles ago[ a premium Carter]. the EGR valve has 5 volts supply, and the valve has no open circuits. EGR plunger works fine off car; spring is fine.

 

The problem is that at 50 mph, there is a 'backfire',or 'hick-up', feels like a NON-ign. 'miss'. When any throttle is given, the 'hick-up' goes away. It idles fine, gas mileage is ok on highway 13-14 mpg at 70. plugs are new. wires are new. no wobble in distributor shaft.

 

Any help would surely be appreciated!!!!!!!!!!!!!

Well. i 'dove' under truck... cat's are fine[heh,heh]... ckd fuel volume.... 1 1/2 pints in 30 sec's[that is above av.].... both before, and after[+/-]. BUT i found what was the matter when i started taking off parts starting with my K&N filter.... when i got to Throttle Body, i immediately saw what the problem was: the throttle blade has a SMALL hole in it[remember doing that? drilling a hole[or holes] in the throttle blade of Holley Carbs when you had a big cam?.

This hole was completely plugged up! cleaned that out, then went and got the 3M cleaner kit from Napa.... the idle is fine, no variation, no codes!!!

Remember, i have 130,000 miles on this!