oy.. another strange problem

[craig]

alright, this one i cant figure out for the life of me. in forth gear, and ONLY in 4th gear, at about 3-3.5K RPM, my engine starts cutting out, acts like its not getting enought gas or something. so i clean and adjust the carb a bit, and still the same. i have no problems with 1,2, and third, just forth. and every once and a while it gets real bad and starts cutting out at 2K in forth (thats about 45-50 on the highway. not cool)


any ideas?

[RSF5]

uhhh.... More cowbell?


Seriously though... Is it running to lean on the highway is the carb getting more air but still mixing the same amount of fuel?

[craig]

i put the original air filter and houseing on(less air flow) and i have the same thing going on. even ran no filter for a bit(perfectly safe. haha) and same thing. could the spark plug wires/distributor cause this?

[craig]

anyone? im pretty much fixing everything today(i have this week off) and would like a quick answer if possable.

thanks.

[stevo]

possibly a coil or ht lead breaking down under load?
happened to me once many years ago very similar scenario turned out to be the ignition coil breaking down under load.
I'm not sure what type of ignition set up you have in your truck, but if you have a distributor it could possibly be the condensor coil inside your distributor or even the distributor cap itself, can't see it being fuel starvation but still a possibility,................. sounds more electrical to me.

[craig]

Originally Posted by stevo

sounds more electrical to me.

yeah, thats what i was thinking. well, i know my spark plug wires are shot. i guess ill just take one thing at a time and see if any of that helpts

[craig]

heres a video of what its doing. as you can see, all my other gears work fine(took them to 4K) but i cant get past 3K in forth. you should be able to hear it pretty easily.

http://www.youtube.com/watch?v=jzGPd8WR3OI

[TerryY]

Changed the fuel filters lately?

If it still does it after filters I would check the fuel pump pressure.

[craig]

Originally Posted by TerryY

Changed the fuel filters lately?

If it still does it after filters I would check the fuel pump pressure.

yeah i changed the fuel filter yesterday. when i took the orginal fuel filter case off(its canister style filter) it didnt have a filter. so its probably been driven for YEARS with no filter.

how to i go about checking fuel pump pressure?

[TerryY]

Is there another filter in the connection to the carburetor?

Had a Chevy van that drove me nuts until I found the damn thing in the carburetor where the incoming fuel line connects.

[craig]

Originally Posted by TerryY

Is there another filter in the connection to the carburetor?

Had a Chevy van that drove me nuts until I found the damn thing in the carburetor where the incoming fuel line connects.

yeah i took the line off and checked, and nope. no fuel filter.

[TerryY]

You would need a fuel pressure gauge teed into the fuel line to check pressure.

It sounds like it is running out of gas in high. Ignition would be a problem in all the gears at the same rpm.

Might be cheaper to buy a fuel pump than a test gauge.

[xsperf]

its probably something in your driveline... also, 4th gear is probably a 1:1 ratio between ur engine and wheels

[craig]

im seriously thinking its something with my fuel pump, because sometimes its worse then before, and sometimes it gets better. if it was the driveline i would imagine it would just get worse.

is it a possability that my fuel pump is slightly clogged?

[craig]

cleaned the carb and put some seafoam in the tank.


problem solved. there must of been something stuck in there somewhere along the line.