Engine loses power when shifting gears(auto)

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JamesMilk

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Wasn't able to do much today, raining all day(I don't have a garage to work in). So I'll be doing the fuel test tomorrow. I already ordered a new tank and filler hose/neck. That fuel tank is leaking and looks like trash. Will keep you informed on the results.
 

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I agree water in the fuel is your first check, then examine all of your vacuum lines. The truck is old enough the vacuum lines may have turned into dry spaghetti and be cracked. A simple check for that is while it is idling, spray water along the intake and along the vacuum lines, if the engine rpm changes, then begin there.
Around here, we have unreal issues with leaf cutter bees - the little devils are quite small, yet VERY industrious. They can plug off small openings in lines in a matter of hours..... and with a considerable amount of material.
Knew a mechanic who had to look at a truck that had been towed in - it would turn over and try to start. Interestingly, the owner had also taken his dog to the veterinarian, as it had been losing weight no matter how much food he gave the dog. Turns out, squirrels had been stealing all of the dog's food and storing it in the truck's air cleaner, in the frame rails.... all over.
 

scrap--metal

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That fuel tank is leaking and looks like trash. Will keep you informed on the results.
Personally, I'd fix the fuel tank before anything else. If you know it's leaking and rusty, it's rusty on the inside too. Your engine and carb don't like orange tinted gas with chunks of iron in it. How bad was the fuel filter when you replaced it?

My K20 had a gutless issue too. It ran great on the test drive, but then it wouldn't maintain highway speed on the way home after I forked over the cash. The fuel filter was plugged with crusty orange sludge from the old leaking gas tank. Replacing the tank and several fuel filters fixed my issue.

I think you'll be much better off fixing the known issue (bad gas tank), and then trouble shooting the remaining issues. If your engine is running on crusty gas, your severely disadvantaged in your diagnostic efforts.
 

JamesMilk

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Personally, I'd fix the fuel tank before anything else. If you know it's leaking and rusty, it's rusty on the inside too. Your engine and carb don't like orange tinted gas with chunks of iron in it. How bad was the fuel filter when you replaced it?

My K20 had a gutless issue too. It ran great on the test drive, but then it wouldn't maintain highway speed on the way home after I forked over the cash. The fuel filter was plugged with crusty orange sludge from the old leaking gas tank. Replacing the tank and several fuel filters fixed my issue.

I think you'll be much better off fixing the known issue (bad gas tank), and then trouble shooting the remaining issues. If your engine is running on crusty gas, your severely disadvantaged in your diagnostic efforts.
Yeah I've already changed the fuel filter once, will probably have to do it again after I replace the tank. It's ok though, the fuel filters are mighty easy and cheap to replace. Then after I get a new tank, I will be focusing on cleaning and rebuilding the carb.
 

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Bextreme04

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Yeah I've already changed the fuel filter once, will probably have to do it again after I replace the tank. It's ok though, the fuel filters are mighty easy and cheap to replace. Then after I get a new tank, I will be focusing on cleaning and rebuilding the carb.
There is also a fuel filter inside the inlet of the carburetor. You need to remove the fuel line and then the big rusty fitting between the fuel line and carburetor body(where you can see it says "Filter"). I bet that filter is also pretty grungy based on the way that in-line filter looks.

I would wait until you are replacing the fuel tank and fuel neck, then when the old tank is disconnected and the fuel lines that connect to the sender are disconnected, disconnect the fuel feed line from the fuel pump and blow compressed air back through the fuel line to clear all the junk out. Make sure you buy and new sender also. If the tank is rusty and nasty, the sender will usually be in even worse shape. I have to replace senders way more often than fuel tanks.
 

JamesMilk

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Yeah gunna replace the whole system, don't want this problem again. And for good measure going to put some silicon sealant around the sender unit after I install it all. It looks like the water may be settling on the tank and entering when it rains.
 

Bextreme04

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Yeah gunna replace the whole system, don't want this problem again. And for good measure going to put some silicon sealant around the sender unit after I install it all. It looks like the water may be settling on the tank and entering when it rains.
Don't do that, it won't totally seal it and it will just hold in any water that gets through and promote rust. Make sure everything is fully cleaned up and new. Then make sure you coat the O-ring with a silicone lubricant(NOT RTV!!! They make real silicone o-ring lubricant and that is what you want). Then make sure that you have everything seated properly and get the locking ring fully turned and engaged. It won't leak at all.
 

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Did you get your vacuum advance hooked up when you put your new distributor in? Also that kick down cable?
 

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will probably have to do it again after I replace the tank.

There is also a fuel filter inside the inlet of the carburetor. You need to remove the fuel line and then the big rusty fitting between the fuel line and carburetor body(where you can see it says "Filter").
Definitely change the filter inside the carb. If that filter has not been changed yet, that could be the sole source of your power loss.
 

JamesMilk

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Don't do that, it won't totally seal it and it will just hold in any water that gets through and promote rust. Make sure everything is fully cleaned up and new. Then make sure you coat the O-ring with a silicone lubricant(NOT RTV!!! They make real silicone o-ring lubricant and that is what you want). Then make sure that you have everything seated properly and get the locking ring fully turned and engaged. It won't leak at all.
Not a lot on there, might just fabricate some sort of cover for the gas tank. The rain just freely enters the top of the tank due to gap between bed and cab.
 

JamesMilk

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Definitely change the filter inside the carb. If that filter has not been changed yet, that could be the sole source of your power loss.
I'll check it out tonight when I get home, was hoping to do this all on Friday when I have the sun, and all the parts at the house.
 

scrap--metal

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And for good measure going to put some silicon sealant around the sender unit after I install it all

Don't do that
I have to echo Eric on that. It's a bad idea. The O-ring and the stamped steel lock ring will seal the top of the tank without any extra protection. Silicone O-ring lubricant is a good idea. It can be assembled without, but that gives the O-ring a chance to bind and pucker out of place. That happened to me once, so I had to re-assemble it after I burned the full tank of gas.

After the reassembly is complete, fill the gas tank up to the filler neck. You'll find any issues with the sending unit O-ring, or the hose clamps on the rubber fill neck hose. If gas doesn't leak out, water is not going to leak in.
 

JamesMilk

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Will definitely try or attempt all of these.
 

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Don't do that, it won't totally seal it and it will just hold in any water that gets through and promote rust. Make sure everything is fully cleaned up and new. Then make sure you coat the O-ring with a silicone lubricant(NOT RTV!!! They make real silicone o-ring lubricant and that is what you want). Then make sure that you have everything seated properly and get the locking ring fully turned and engaged. It won't leak at all.
^what he said.
In addition, after I got my tanks senders cleaned up and plumbed in, I coated them with some fluid film. To keep the rusty crustys away.
 

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I have read all of this.

Don't leave us hanging in the wind.
It has been 10 days since the last post was made and we all want to know how it turned out...
 

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