i know this topic has been beat up a little but searching through other threads i couldnt find a definate answer.

here is what ive got... 98 12v wont start unless i bump the throttle just a little, but it comes and goes, sometimes it fires right up and sometimes it will not start at all unless the pedal is pushed, all fuel lines have been replaced so i know that is not an issue,

i saw that some said it was the starter and some say to bump the idle up a little. anyone know a for-sure cure? i picked up a photo tach today and going to set the idle tonight, what is the spec for idle w/manual trans? 800-850???

 

With a manual in neutral with A/C on 750-800 rpm

What do you mean? Short lines or all of them?
If the hard starting correlates with tank level you might have a leak in the steel line on top of the bell housing.

 

sorry... i replaced everything from the pickup tube to the IP and the entire return....

 

Ok great, so if the hard starts are related to fuel tank level and assuming your new lines are leak free the only place left to look is at the pickup tube in the tank module.

Sometimes a failing lift pump will cause hard starting depending on which end of the truck is facing uphill.

Main thing for you to do first is to figure out what the situations are that cause the hard starts,

 

well i used steel lines with inverted flare fittings, so almost impossible to leak and i have a fass system and fuel pressure gauge. all that seems to be normal. at first it did seem to go with the fuel level but then it would do it any time, full or emty, warm or cold, sometimes after it sat over night and sometimes after sitting for 5 minuets. just seems strange...

however, last night i adjusted the idle to 800 rpm with the photo tach, and also found that the jam nut on the adjuster seemed to be a little loose, Oh, also was idleing at 630 rpm w/no a/c. even though the tach in the dash looked to be about 750 rpm, so far it is starting with just a bump of the key and no pedal, so... maby...