1996 help with loss of power

[oneofmy3]

Well boy's im in need of some help again.My truck has been (running off) kinda stumbling when i am driving. Got a buzz test done and good news is all past the test. Did the cylinder contribution test and not good news. Cyliners 3,4,and 7 are not helping the motor run (failed the test). The truck has 360,ooo mi on her but does not burn oil and does not smoke out tail pipe. Any help? I hope it is not rings,could the injectors be bad but pass the buzz test?

Thank you

[BigFuel]

All on the same side and next to each other huh? Check the pigtail going to the that side of the head looking for damage/melting.

[madpogue]

Originally Posted by BigFuel

All on the same side and next to each other huh? Check the pigtail going to the that side of the head looking for damage/melting.

No, they're not. 4 is on the other side. They're all three on separate UVCHs.

[BigFuel]

DOH! My dyslexia fouled my hypothesis.

[oneofmy3]

There is also a code p0113 =air intake temp sensor and PO 3444= CPS the cps in the truck now is the gray one is the grey one a bad one for my year? i have herd all kind of stuff about CPS's dont know what to do blue, black, or grey.

[BigFuel]

Is the Air intake sensor clean and not hidden or buried away under something?

Buzz test just sees IF the injectors pulse, CC Test tests the quality of the injector's pulse (I.E. the injector opens but only moves half the volume of fuel resulting in a less then balanced total injection pulse that includes all the cylinders or simply rough idle/cruising/accel). With the engine running do the "oil cap test".

CPS: dark blue original Ford (had issues), replaced by light blue or grey (still had issues but Ford concidered it "within spec"), black is the one from International not Ford (IMO the best there is). I buy International parts before Ford parts.

[oneofmy3]

Thank u. Big fuel ......"oil cap test "is to test blow by correct. If so all good on that half with cap off there is some blow by but cap upside down over hole it does not blow cap off.

[BigFuel]

Right, if the cap stays on then there is not likely sufficient blow-by on three cylinders and it's the flow of the questionable injectors at stake. When was the last fuel filter change? What does the fuel filter look like? Clean and white? Run a fuel stabilizer/cleaner through the system for a couple weeks and retest.

[oneofmy3]

i just did fuel filter change about 1,000 mi agao the old one looked good. i change fuel filter every oil change about every 4,000mi. i also run PS (power service?) fuel stabilizer with every fill up

[oneofmy3]

YOu migh be on to something tho i have never used the rear tank (has hole in it). But the other week i did by accident flip to the rear tank for a very quick sec. when trying to turn off the headlights and i hit the switch. I bet i put all kind of trash in to the fuel system.