loss of acceleration with 1986 ranger

[cyborgv1]

I've noticed a severe loss of acceleration up to 25 miles per hour, with noticeable vibrations. The vibrations are also present at about 50 mph. Mid range acceleration seems to be fine, but getting above 60 is challenging as the engine seems to get stuck at 3000 rpm. On hills the engine holds 3000 rpm's but loses speed. The engine appears to be running fine with no abnormal sounds when revving up to 4000 rpm in neutral. First noticed the problem half way through a 700 mile trip recently when I stopped for the night i a snow storm. I have slightly oversized tires. I also replaced the distribution cap, rotor, and the tfi-iv ignition module to correct a problem where the engine would stall (even at high speeds) when hot, and would fail to start until it cools down. Plugs look clean and cables were replaced not too long ago. Transmission fluid looks good. Engine oil was recently replaced and looks good as well

Engine has about 170000 miles
Automatic transmission rebuild less than 50000 miles ago
Will post engine codes when I get them read.

Thanks in advance for the help.

 

[IMenriched]

things inproved for myself as well with a new TFI...
when I changed the fuel filter the mid-range studder was gone.

It could be the intank pump is not working...with aid of a friend (a trusting friend), draw straws to place a hand on the tank...then turn the key to the on & off with a few seconds delay for each way. ( DO-NOT start!!) Whoever with hand on the tank...should be able to feel the in tank pump activate, each time the key is turned on for Just a few seconds and then it will turn off, don't be alarmed they're suppose to do this.

You also should hear the inline pump on the frame rail, turn on too.

Now that doesn't neccesarly mean you're gettting correct pressure out of your pumps, just that they are working.

Double check the vacuum lines for leaks, don't forget the brake booster...and the Cruise control if so equiped.

 

[cyborgv1]

Thanks for the help. My truck stalled again. I had my friend turn the ignition on while I listened to the pumps. Instead of the usual pump hum, I got a more sick electrical sound from back there. At times it even gurgles. Thanks again for the tip, would have never thought it was a fuel pump. The best news is that I'll finally get the chance to fix the fuel gauge.

 

[IMenriched]

The gurgling is a sign the the main pump is cavitating....
& yes it could be the in tank pump not working correctly....A cheaper approach would be to change the fuel filter....but if you got your heart set on curing the fuel guage then by all means, swap out the in tank unit...as long as it is open...might as well.

if you do not have the inline metal fuel filter you might have the resivour canister filter, this is what I had. It located just up stram from the tank near the transferr case, 86 was a split year for that, could have either the canister or the metal inline after the main frame rail pump.

 

[cyborgv1]

I tried to get away without replacing the in tank pump. Pumps aren't very cheap. I replaced the in-line canister filter, and nothing really changed, so I replaced the in-line rail pump, and it sounded allot better and ran a little better, but there was still the gurgling, or no noise/vibration from the tank pump, and it stalled after a short drive. I ended up replacing the in tank pump which was not an easy task. The strike plate hasn't been removed in at least 8 years, but it runs great now, still a bit of vibration but no noticeable loss of power. After I had the tank off, I noticed there's 2 filters. One is the in-line metal filter, and the reservoir canister filter. Not sure why there'd be 2 filters. I'm thinking of removing one of the filters but I'm not sure which one would be best. Right now it's set up with the in tank pump going to the canister filter, then the in-line rail fuel pump, which goes to the in-line filter. Any reason why I'd have 2 filters like this?

 

[IMenriched]

I tried to get away without replacing the in tank pump. Pumps aren't very cheap. I replaced the in-line canister filter, and nothing really changed, After I had the tank off, I noticed there's 2 filters. One is the in-line metal filter, and the reservoir canister filter. Not sure why there'd be 2 filters. I'm thinking of removing one of the filters but I'm not sure which one would be best. Right now it's set up with the in tank pump going to the canister filter, then the in-line rail fuel pump, which goes to the in-line filter. Any reason why I'd have 2 filters like this?

1st off, Glad to hear it is running better
who knows why 2 filters??? Some have opened up the canister only to find that there was no filter in there...but you may have one in there, IDK.
If the cansiter does have a filter in it then...it should be changed ...it should be the 1st filter out of the tank or up stream, as you already know...So if it is clogged...then your still limiting flow to the rest of the system.

 

[cyborgv1]

After a few months of driving, I finally discovered the cause of the vibrations. The U-Joint between the carier shaft and the drive shaft was going bad. It was a strap on joint, and it looks like one of the straps, or mounting bolts broke. Or maybe the joint seized up and broke everything. I'm not real sure as it finally fell apart when I was going about 65 mph... I couldn't get the rear shaft off so... I held it up with a c-clamp and belt and drove to a shop in 4x4. This fixed another slight but annoying problem present when I got the truck. This loud smooth hum at high speeds. Everything runs nice and quiet and alot more smooth. And because everyone likes pictures of broken parts... here you go...