Help no power after warm up

[jcap]

1994 B2300

I just got the truck, I replaced the head and all the usual top end stuff as well as complete brakes and numerous other stuff. It runs great, (a bit of hesitation but it is a 4 banger with 200K plus). The first time I took a long ride the truck loses all power after maybe 20 to 25 minutes. It doesn't die or stall just bogs down with no power. If I let it sit 20 minutes its fine but the cycle repeats itself. I didn't check codes yet, but I did make a few changes that I am hoping someone can tell me if they could be an issue. I put in a oil, temp and volt gauge trio and removed the factory senders to utilize the ports (new gauges are mechanical), I did leave the temp sender that is in the heater hose connected. I also removed the RABS solenoid so I have a dim brake light and the yellow ABS light lit on the dash. Can disconnecting any of that stuff be causing my issue? I did the basic check all connections, check vacuum lines , fuel filter, its not overheating. I will go back to where I had to leave the truck now and see if I can figure out getting codes from it ( I am used to modern OBDII) and report back,

any help would be appreciated!
Thanks

 

[RonD]

Fuel filter or fuel tank pressure lock could produce those symtoms.
Fuel filter is $10, replace just because.
Run truck with gas cap loose, so air can get inside, this will test if fuel tank is getting an air lock after fuel is pulled from it for awhile, EVAP system could be the issue if this works.

On fuel injected engines there are two coolant temp sensors.
The sender for the dash board gauge has 1 wire.
The sensor for the computer has 2 wires, it acts as the engines "choke", it tells the computer the engine temp, computer then runs engine rich with advanced timing until it warns up.
Once warmed up the O2 sensors help computer maintain correct mixture.
If this sensor is not connected or not working then you should get a CEL on the dash and engine would be stuck in "choke", open loop, mode until repaired.

The MAF sensor on the air intake tells the computer the air flow into the engine and the air temperature, this is the main data used by computer to set air/fuel mix ratio, warm or cold.
The MAF can be cleaned to assure it is working well.
http://www.therangerstation.com/tech_library/CleanMAF.html

 

[FritzTKatt]

I'm going to guess the new senders are confusing the computer if they're even connected. The brakes won't make a difference.

 

[Andy D]

wabbout a clogged cat? bad coil?

 

[jcap]

I gave up. It was not the fuel filter, the coil packs were new, I tried running with the gas cap off and on, all connections were tight. I brought it to a local shop who diagnosed a bad fuel pump. The whole assembly from mazda is $300 plus, just the pump can be had from rock auto for $50, The assembly includes the sender and mine never worked right and I hope to never drop the tank again! So I was leaning towards the mazda assembly, anybody have experience with the replacement pumps or thoughts? I had a bad experience with a cheap replacement in tank fuel pump on a mustang once

 

[RonD]

Cheap pumps can(will) cost you more in the long run, if you are keeping the truck.

People say if you can get the help of a friend that taking the bed off is easier than dropping the tank.
I have dropped the tank and it is pain, never pulled off the bed.

 

[mn_smokeater]

Take the bed off. It if I recall 6 bolts. Soak them down ahead of time with PB Blaster or the like. Make sure to get replacement bolts for any breakages.

 

[jcap]

Thanks guys,

I went for the original Mazda pump, and having a shop do it

 

[Haywire6000]

TAKE THE BED OFF!!!!! I just did a pump in my 93. No joke took about 20 minutes my taking the bed off. Actually didn't even need to take it off. Take out all six bolts and pick up drivers side and wedge a long 2x4 or something to hold it up. I did that for mine and made it super easy.