20 Most Recent 2001 Ford F150 Styleside SuperCrew - Page 7 Questions & Answers

Check how old the battery is & test it or replace,as necessary Test Alternator Output especially A/C Current Ripple Look at ALL Data with professional scan tool on a road test & record things Look at freeze frame data when problem occurs

DTC P1131 DTC P1151 indicates the system is correcting RICH for an overly LEAN condition. The Heated Oxygen Sensor (HO2S) voltage is less than 0.45 volts. This is usually due to a vacuum leak after the MAF. It can also be caused by a bad PCV valve or PCV system hose. It can also be caused by low fuel pressure or a plugged injector.

Start with the simple and clean the MAF and the IAT sensor. In simple terms, the engine is running lean and is being compensated by the ECM. P1131 is bank 1 and P1151 is bank2

Good luck and keep me posted.

We may need more details. Does your 4wd dash light illuminate? Do you hear clicking from the dash? If it does not, you are dealing with a fuse or transfer case issue. If you see the light and hear clicking, it likely is not your transfer case but either your 4wd solenoids (attached photo) on the passenger side firewall or the actuator on the front differential. Pop the hood and listen for clicking from the solenoids, if the click, direct your attention to the actuator. It is vacuum actuated so it should move about an inch when engaging and disengaging 4wd. It sometimes gets stiff so see if you can move it by hand to free it up.

That is a hard one to call without seeing it in person. It could be a clog in the heater core (have you ever had it flushed?), a bad selector switch, or a bad blend actuator. I think the F150 of that year uses an electronic blend actuator similar to the one used in the Explorer (some of them are vacuum while some are electric), you'll have to look at the box to see why type it uses or if you can pull the panel off, check the back of the hot/cold switch. See if it has vacuum lines or an electrical connector. I know the Explorer has a fix kit because the electrical actuator will strip the gears and not change the door position easily or at all.

Sounds like the rear end differential is going out. I had a similar problem on a customer's truck, and it was the differential in the rearend. Replaced the rearend, and the noise was gone.