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1985 2V Throttle very touchy

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I recently purchased a 85 mack r from kentucky i drove it back to iowa no problem , lately ive been driving it and the throttle is all or nothing anything in between sounds like im hitting the pedal 30 times a minute , as much as i try to hold it still i cant , its to the point people look at me like im doing it on purpose , ive tried a tighter return spring and looser spring , no difference , also not sure exactly what engine is i know its 2 valve but the tag says meets emisions of 1990 , and i cleaned off front cover below a/c comp where numbers are and theres nothing there and data tag has half of the numbers and setting gone like they were never even stamed , i wanted to figure out low idle , and not sure where to go with this its very annoying to drive it has american bosh pump . any help would be appriciated

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Gudday M8

when we had much the same problem we found the gas pedal arm on side of fuel pump , the spring in the arm twaz broken

th@ doohikey was fixed by putn in a new arm

the arm is spring loaded so U wont overload the shaft n do damage to the internals of the fuel pump


U fly by wire





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Try to connect the throdle linkage futher out on the lever on the governor. But when you get thru with it make sure your still getting full throdle with the foot petdal.Also the cab and engine mounts being bad will let it jack up and down fast.

glenn akers

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