Is there a maximum speed for high 4x4 on the 2008 f-150 supercrew?

Hi Diego

78mph, downhill and a following wind :>)

The maximum speed of the 1961 Fiat 600 4 cycle 28 HP is 78 mph. ... Which was the maximum speed of fiat 600 4-cylinder 28HP 1960? 3The maximum speed ...

high speed and heavy braking will produce a pulsation in the pedal
that is the abs working properly and the pulsations are the brake release and reapplying
intermittent abs light indicates a wire or wheel sensor problem at one of the wheels

depends on area and if its limited by the ecu. but between 90 and 135 but high end can cause damage.

Call it 80 miles per hour with a strong tailwind.

Cars of that era/engine size were all 'wheezy and asthmatic' once they got to 60mph and to be perfectly honest, they weren't designed for high speed motoring.

Can you replicate this in the workshop by raising the engine revs with the pressure gauges attached to he high and low sides? What is the maximum high pressure you see before the system shuts off?

blower motor resistor.

U could try turning if on high and smacking the fan with a rubber hammer under the passenger side dash, if no go, try checking for power and ground at the fan motor, if you have no power to the fan check for power at the fan speed resistor, then finally check for power out of the switch, always check all your fuses prior to troubleshooting electrical problems , it will most likely be a bad fan motor, then the switch, then the fan speed resistor please rate

I can give you a few tips on this but you need to check the specifics for your low and high A/C pressure switches. The 45 sounds slightly high.

What you want is to have your A/C compressor running steady for maximum cooling. This means the charge pressure is moderate and it keeps the pressure cut-off switches from deactivating the compressor clutch the longest. The pressure is high enough to keep the low pressure switch from activating and low enough to keep the high pressure switch from activating.

These switches can usually be changed without losing Freon. The spring resistance can weaken, changing when the switches work.

There is a difference in the Freon oil charge for different makers. This can affect performance and durability. The filters you mention are often contaminated when the system is open through complete Freon loss.

Another way of looking at this is a 45 psi is suppose to be Freon. All is good when it is pure, but if contaminated with ordinary atmospheric air, it can not work as good or even at all.

There are some other products you can use to clean the coils and such. A foaming product is sold at stores like Lowes or Home Depot. Theory is it works like shaving cream, expanding in the fins and pulling dirt out. You then flush with water. Check label warnings for use on different metals.

Find out when the cut-out switches are suppose to activate and what your recommended switch thresholds are. Hope this helps.

that sounds like the blower motor resistor. on high it bypasses the resistor for maximum speed. but on low or medium speeds, the resistor slows down the blower motor. when the resistor goes out, the blower motor will only work on high. it is an inexpensive part and easy to replace. it should be located on the black box under the dash on the passenger side. there might be a plastic cover over it, but it will have a 3 or 4 wire connector plugged into it