83

I was driving from Helena to Missoula, takes me about 1 1/2 hours. About a half hour from Missoula I was starting to feel something weird, like I was losing power or something was binding or sticking and it would slow me down slightly. Wasn't super noticeable though, I was at first trying to figure out if there was an off-&-on headwind.

On the way back to Helena later that night, it started doing it again. This time though, worse. It would really start feeling like I was hitting the brakes. If I gave it more gas it got worse, and eventually would start bucking. Being the smart guy I am, I decided to just push it to Helena rather than turn back to Missoula and stop at a parts store.

So, only at highway speeds, I'd be cruising along at 65ish, then it would start feeling like I'm hitting the brakes, and if I let off the gas it'd be better, if I pushed harder on the gas, it would buck and get worse. This would get worse & worse until I was moving down the interstate at like 35mph. If I pulled off and stopped for a bit, I could then go another few minutes before it would start acting up again. Driving around in a town at low speeds I couldn't notice it happening.

So all I could figure is a fuel issue, and I figured fuel filter, right? So I replaced it and it's been fine. BUT, it really only happened before when I was going on the interstate for an extented period. This was about 2 months ago. I told myself I'd get back on the interstate and run it for an hour or so to make sure the problem was gone, but never did...now I'm leaving tomorrow for Arizona....and I just remembered this issue.

Am I right? Fuel filter, problem fixed? I could coast fine so it's not engine or tranny or axles binding up. As long as I wasn't giving it gas, the problem didn't occur, so it's got to be a gas issue right?

Give me ideas of what I can stress about tonight if you can think of any other things that would cause this! Sorry for long post and thanks if you read all the way to here.

BT17R

Get a AAA Premium membership before you leave.

83

Yeah I keep meaning to do that...
I remember you giving me some advice on my other thread, thanks for that. If you checked up on the thread you saw I'm not pulling the trailer, they'll just be loading the back of my truck with stuff, which is good. I'll look into AAA.

crazykooter

It can be many things causing it but the 1st place to look is the fuel filter. Its cheap to replace and should be changed often anyhow. Second place to look is at the float lvl on carb. I am sure its ok but check anyhow. Then look and replace plugs,cap and wires. They are also cheap. Heck it could be a vacuum line which is causing a sensor to read wrong. So on and so on.

okie81

Vapor Locking?

crazykooter

If it was vapor locking it would more or less kill the engine. Since it has a carb I would say its not but hey ive been wrong many times before.

Al's Chop Shop

my first thought is vapor lock. but i would also check for a plugged cat.

Al

83

Really? Vapor lock? Can you explain it to me? I though vapor lock was when you suck water into the cylinders?

The plugs/wires/cap/rotor are all less than a year old. It's actually a rebuilt carb since the time this all happened, too.

83

Ok I did a very quick read on vapor lock (not hydrolock )and it sounds like it often has to do with heat and high altitude making the fuel vaporize too early? This happened to me in March...maybe February. I'm always at high altitude here. And one of the solutions a person talked about was downshifting and really giving it gas on hills. With my truck, giving it gas aggravated that problem rather than helping with it.

I'll do some more research and hope it was the fuel filter. If nothing else, if my spark system is up to snuff, we're in agreement that it's a fuel issue? My pump is also brand new.

83

I know my charcoal canister is not plugged, I guess I should make sure the gas tank vent is also not plugged? Would buying a vented gas cap help (assuming vapor lock was the problem)? If it's caused by heat and high altitudes...it was happening in Montana in the winter and I'm about to head to Arizona...80's there right now. That won't help.

fyreandwater

I would vote for fuel filter, same thing happened to me.

okie81

If you concur that vapor locking might be the issue, you could try adding a spacer between the intake and the carb; that dissipates a lot of the heat from the engine and has worked for me in the past.

Steveh29

This happened to me one time and ended up being a clogged cat. Got a local exhaust place to swap it out and everything was OK after that. I don't know if your truck has one, but it's something else to consider if the fuel delivery problems end up being a dead end.

Sked

Id say fuel filter ive been there too many with these trucks and it sounds like that. I carry an extra in my glove box since it happens so much to me. If I go down logging roads for say 2-3hours I NEED to change the filter, ive even found ladybugs and ants in my filters... lol i dont know

83

Sweet. Yeah, I had been meaning to have an extra in the truck for months...you better believe I've got an extra now!

The cat is also less than a year old, which I know doesn't completely rule it out, but still..At least I know what to check for if it happens again.

My carb does have that plastic insulator, so I'm good there.

Thanks everyone, hopefully it'll be an uneventful trip (mechanical wise)!

83

Well, made it to Salt Lake City with no issues, and I could even go the speed limit pretty much the whole way! So far the truck seems up to the job. All the extra weight in the back hasn't seemed to affect the power at all, just the stability a little..

okie81

Good to hear you made it.

foskco87

exact same thing happened to me. Changed the fuel filter, took it out for a test drive, bucked once and hasnt done it since. I have been on several 2+ hour highway trips since then and it hasnt bucked once. I also noticed that when I first started driving it wouldnt buck but the more the engine warmed up the more it would buck so that might explain why it wouldnt be as bad when u were letting it sit for a few minutes. fuel filter would make sense cause your engine is still running but is just losing power for a split second so a plug in the filter would mean pockets in your line which would account for the sudden loss of power. If it was something more serius your engine would probbaly stall, or atleast I would think.

83

Well I made it there and back. Fuel pump (3 month old fuel pump) went out south of Salt Lake. I rigged it with some electical wire and it got me to the next town, got a hotel and bought a new pump the next day. Did fine on the way down otherwise. On the way back the same stuff I described in my first post started happening again. I replaced the fuel filter and it was fine the rest of that day. About 2 hours into the next day...same thing. Replaced the fuel filter and made it the rest of the way home fine.

What do you think? Is the filter just a placebo and it's something else that's coming and going, or what do I need to check if I'm really plugging filters that quick? Drop the tank and clean it out? It's not rusty.

Sked-how would logging roads clog your fuel filter? I mean it's a more or less closed system, right?

yotaboy82

check your oil.....my fuel pump went out and my oil turned to gas rather quickly