truck help - I HATE FORDS

[84gmcjimmy]

I HATE FORDS! I tell you, I almost started liking our '81 f-250 but we went out and looked for a Christmas tree this week...

I Tried this in the right forum for a bit, but not too many replies, so here I go!!

It has a 4 speed, and I think a 351. In first and second it is fine, but when I get to third it doesn't move. I can idle, but when I try to accelerate it chugs and is really sluggish.

I gave up trying to drive it, and we came home. On this main road there was a huge logging truck right on my tail, and I'm only going 25km/hr of the posted 50 km/hr. I couldn't move any faster and I couldn't pull over even with my floor fullly depressing the gas pedal. I don't get it.

I got it in second and reved the dingles out of it, then it ran okay for a bit. It was almost like something was stuck or gumed up. The automatic choke is sticking too, which is a pain.
What a gift...we are trying to sell it and now it runs like diarehha.

Any help?

My uncle said it might be the fuel pump, but if it was, wouldn't it have the same problem in each gear??

 

[big_black_blazer]

maybe vacuum. pull off a small vacuum line while it's running and see if it makes a difference (worse). if it doesn't make a huge difference, then that should mean it is vacuum. spray carb cleaner around your vac. fittings, hoses, and carb base. it should rev higher when you hit the leak.

 

[theitalian404]

is your choke man. or electric?? I gotta a 2bbl elect. on my K-10...and I just disconnected the pos...I was tired of focking with it. and yeah, check your vac. I doubt it's your fuel pump. your fuel pump would work the same, regardless what gear your in...just how much your on the skinny.

 

[84gmcjimmy]

I think its manual. But my grandpa said its "automatic" ? How do I telll man. vers. elect?

 

[BozoWise]

Electric has wires off the choke the manual has a tubular line run to a heat exchanger.

 

[diesel4me]

sits a lot??

If the truck sits a lot,it could have a lot of varnish in the carb,and the power valve could be sticking or blown..most of those 351's had a 2 or 4 bbl Holley/autolite carb that used them -

-First thing I'd do,is I'd put some carb cleaner and or dry-gas in it..might have water in the gas from condensation,that will make it lay an egg under a load..then wire the choke fully open if you have too,to make sure its not just the choke closing up on you when its not supposed too!..see if the air cleaner isn't clogged,or full of mice nests too--you'd be suprised how many I find in vehicles that don't get driven often or very far..

Also weak spark due to bad wires,weak coil,pick up coil or module, or cap and rotor,or fouled plugs will make the motor crap out when its under load--like in higher gears or going uphill--see if the vacuum advance works too..usually,if it will rev up good in lower gears or light loads it isn't a fuel problem,but its easy enough to check the fuel pump pressure and volume..

But being a FORD,it might have other things wrong too....good luck,you'll need it..

 

[gmtech954]

most likely a fuel filter imo

 

[dave_90_blazer]

Electric has wires off the choke the manual has a tubular line run to a heat exchanger.

automatic is any kind that opens on its own, manual has a control cable run inside to be pulled by the operator to close the choke, and pushed in to open it

 

[BobK]

Might be the timing chain.
Just replaced one my brother-in-laws 86 F-150.

It would idle but once the RPM went up under load she wouldn't go too far.Like you said,you could floor it but nothing would happen.

Timing gear set was replaced(cog's and chain),oil change x2(old oil was like black gas,that's how saturated with gas it was.)New plugs,wires,cap and rotor(basic tune-up crap) and she runs like a champ now.

Just something else to check.
Good luck