88 F150 4.9 5sp 4X4 1 tank

I have only had this truck for a week now. It sat for a while, and previous owner had new tranny, clutch, and fuel filter put on.

I tried reading through some posts to answer my question, but all the ones I found don't seem to quite fit. Different motor, dual tanks, etc...

Problem:
I am experiencing some loss in fuel pressure when the truck is under load. It will start to accelerate, and then lose gas(I'm assuming) and if I feather the pedal I can get it back.

If I don't accelerate too hard, then I can keep it from happening most of the time.

I have changed the fuel filter twice, and each time the gas from the dirty side of the filter had a rust color to it. After the first change, the issue went away for a couple days. After the most recent change, it was happening immediately afterwards, though not as bad.

My guess is there was rust in the tank, and it keeps clogging the filter.

I understand (from reading other posts) that I need to attach a fuel pressure gauge to make sure it is a fuel pressure issue. Have not done this yet. I will if I need to.

My questions are:

Should I drop the tank and clean it?
Change the tank?
If I do drop the tank, should I change the internal pump?
External pump(looks old)?
Could this be something really simple, like a relay?
Do these symptoms fit my assumption?

Part of the reason for getting this truck, was to learn how to work on it. I have the Haynes manual, but not sure where to start.

Thanks for any help.

 

Usually it is recommended to go through a newly purchased used vehicle in detail.

All regular maintainence issues should be addressed, brought up to date.

All fluids should be checked and changed (the trans should be fine).

A full tune up should be performed if needed.

Brakes, wheel bearings may need attention.

You really must test your fuel pressure beforehand, but you won't be comfortable until you pull the tank and eyeball the interior.

If the fuel pump in the tank is original, I personally would change it in a heartbeat with a good quality piece while the tank is out.

 

Thanks!

I have intentions of doing a full tune up myself. It looks as if the previous owner started the process. Plug wires look new, belts look new, and he gave me a list of what he was going to do next, including the brakes, bearings etc...

However, I want to get this issue addressed first.

Given the rust color in the gas, and the loss of acceleration, am I definitely dealing with a fuel issue? Or could there be another, non fuel related problem causing the symptom?

 

Generally, even if a vehicle is brought into a shop with a problem, it's a first step to replace plugs,cap,rotor,and at least ohm plug wires for a resistance reading, if these items were beyond their sceduled replacement.

Though you may have a rust color in the fuel , the hesitation you're experiencing may be due to another factor.

Any truck with an in-gas tank fuel pump with 150K miles should almost be considered expendable just for the reliability factor. At least from my viewpoint.

The fuel pump on the frame rail is a relatively easy piece to install.

Consider at least, possibly, a Haynes manual and code reader for an EEC-IV system so you'll be off on the right foot.

 

Update
Truck cut off on me while driving today. Left me stranded. It just choked out. I could get it to start but it was a really rough idle, and eventually it would die. The gas pedal was having no impact.

I have the Haynes...I'll have to get the code reader. I saw where others said there will be codes, even without a check engine light.

I'll have my normal daily driver back tomorrow, and I'll be able to work on the truck soon.

I guess I'll start with the plugs and move onto the tank.

Thanks

 

That cut out sounds like a good time to get your fuel pressure readings, as the truck won't die like that from plugs.

But with the Haynes you'll have baseline information, good move.

 

I was able to get quite a bit done to the truck. I changed the tank and sending unit, and haven't had any further issues. Thanks for the help.