decil

hey guys i got 89 f150 5.0 here is what is going on i will try to give as much info as i can. the truck over the past few months has had new high pressure pump and new tank pump in rear tank front dont work and is not used. new fuel filter.

ok so here is where it started going down hill went on a camping trip and on way from house to gas up truck started bucking after pulling out of red light and was not responding well had to feather the gas pedal to keep it alive and assumed i was out of gas. hence forth the trip to gas station. got it off road walked about eighth of mile up road and got a gallon she fired up and i filled up. ran great

On my way home from camping the truck does this weird hesitation thing hard to describe but it doesn't buck just acts like its running out of gas or you are not giving it gas and then after two or three seconds its like being on a two stroke hitting the power band just takes off. does it quite often now.

ok so i get home truck wont idle for crap surges. new idle air control. that just made it not surge as bad was going from like 400 rpm to 900 new IAC and like 500 to 700 rpm.

checked rail pressure and at 32 ish psi pull vac hose to regulator and jumps about 5-7 psi which is good from what i understand however the needle on gauge kinda fluttery. and by that i mean it would be 32 to 31 psi back and forth real fast like and this followed with regulator unplugged. did a leak down check and found leaking injector.

so finally replaced all 8 injectors with 4 hole remans cleaned crap out of my intake and throttle body new throttle body and intake gasket it starts and idles great now. however took test drive ran good for about 10-15 min then on way back started bucking feathered gas till it pulled out of it and put 20 bucks gas in. on the way back it started doing that weird two stroke thing like you are lugging it didn't buck and then bam starts scoot down the road

sorry for the length i am really starting to doubt this is fuel related its late haven't checked rail pressure since injector install will in morning any ideas i would hate to start wasting money on a goose chase i got wife three kids and i the only one working. so any help would be great thanks

decil

ok so i checked rail pressure this morning and it was rock solid. i still had warranty on high pressure pump so i was gonna take it off and get new one just to be sure it takes 10 min and free so why not then look into ignition stuff and what not

here is what i found i discovered that where the two vac line on throttle body y into one had a split on the bottom those lines then run to evap canister. i pulled vac with my gauge and those lines only pull vac off idle and i think i was getting between 15 to 20 at the highest points.

i replaced all with new lines and truck runs good now will have to drive few days to find out for sure but does make since it only gave me fit on curvey roads wide open under load or lugging it in high gear that is a lot of vacuum to be loosing so we will see. i will keep my fingers crossed that this 1.50 fix is the ticket and post back later just in case this could help any one else down the road

decil

did good for about 40 mile now back to its old tricks again. so nobody has any advice at all???????????????????

87f-150

I would take off the neg battery cable and let it set for about 5 mins so the computer can go back to the factory setting and relearn its idle then go drive it for 10 miles.
If that dont help start check the computer for codes.

decil

battery disconnected and no luck no codes showing at this time.

87f-150

Does the computer flash a code 11

decil

yes it flashes 11 system pass i really gettin stumped on this one maybe time to sell it off and make a payment on something... ehhhh prolly not

decil

i looked and i am pretty sure i am rite, but having brain fart 89 didnt have a crank or cam sensor rite?? i think that was later on. seen lot of chains get sloppy and cause studders and bucking in vehicles that have those

87f-150

89 didn't have the cam or crank sensor.

decil

alright just to make sure all my bases are covered on the fuel side i removed my inop front tank and removed the transfer valve. spliced my nylon fuel lines with nylon splices not rubber hose. new fuel filter and turned in my high pressure pump on warranty for new one just because it did kinda act little like this when it went out about a year ago. so gonna drive it tomorrow if it still is actin up gonna look into new distributor. any one have any experience with those going out do the cut in and out or just die all of a sudden. all my distributors in past have been gm hei or points syle. also any one ever have things like this happen due to sloppy timing chain?

THANKS