ok so i replaced my blown brakeline with a brand new one
bleed the brakes and master cylinder
today i went to drive the truck around and it started the problem i thaught i fixed
i was driving at 25 mph when this happend
it does really good at 35-75 mph
the rpms dropped below 600 and then died out
did it 3 times today when i was brakeing
i have replaced the following
all vacum lines iac valve
egr valve
fuel filter
plugs and wires oil and oil filter and trans filter and fluid a month or so ago
i changed both temp sensors
altenator 105 amp as the auto parts store wouldnt sell me a 120 amp or 140 amp
power steering lines
rear brake line next to fuel tank

like i say i bleed the brakes and master cylinder
then i drive it today and it dropped the rpms lower then 600 then died out
it starts back up fine but its surges when it idles the rpms go to 1000 then drop then go back

i will be replaceing the intake manifold gasket soon

i am really stumped maybe its the throttle postion sensor or even a stretched throttle cable
im not sure
any ideas
and yes the fuel pressure is normal at all ranges startup idle and with the key in on just before start postion

of where else to check
and the truck isnt throwing any codes

could it even be the power booster vacum line leaking still
also could it have something to do with spark i did check that and it does get spark but sometimes i dont think it does as it seems like maybe its cutting out it only has the problem of the rpms droping when im driving at or less then 25 mph and or braking not hard braking just braking to slow down
on the high way it runs great

 

Dont know what year your truck is, but if you have a MAF, check that !

 

Check your brake booster. The lines may be good but the internals could be shot (i have a diagram of brake boosters too in my book lol)

Because when you hit the pedal the booster takes some air from the intake to make a vacuum and if you have a leak its going to take too much and kill your car.

i tested this on my old car by actually plugging the line that went into my booster and relying on manual brake power. if you can hit the pedal and slow your truck down without it shutting off its your booster

 

its a 94 and it does have a maf i completely forgot about them having one so ill check it thanks

 

thanks ill try that
so if i remove the vacum line and plug it
then it becomes manual brakes and it doesnt die its my brake booster
i am just trying to clarify cause i may give this a try later today at least once around the block a time or two

 

Yeah if you are able to take the line off and plug the line (just make sure the plug is big enough to not get sucked though!) you will be exerting all the force to your brakes without the help of the booster. But if you can slow your truck down and it doesnt shut off then your booster is bad or you have a leak

Thats how i diagnosed my truck when my booster went bad

 

i was gonna use a piar of vice grips it did stop the air flow to my booster
i didnt drive it around the block just back and forth in the driveway
not enaugh to tell yet but tomorrow at work i will get a bolt big enaugh


also would i have to plug the line that runs to the enging or jsut the line to my booster

and my truck has a manifold absolut pressure or map sensor
not a maf as i thaught

 

all you have to do is take it off the booster and plug it

 

ok thanks