Mechanics

EMISSIONS/FUEL/SENSORS

2002 Ford Ranger

Engine Performance problem
2002 Ford Ranger 6 cyl Two Wheel Drive Automatic 150000 miles

About thirty minutes into my daily commute home, the vehicle started loosing power, no matter how hard I hit the accelerator the truck would not go over 50mph or 3100 rpm. When the truck is in park it wouldn't rev past 3100 rpm. Put in a bottle of B-12. Ran good for 3 weeks. Happened again about 30 minutes into drive home, stopped put in three gallon of gas, which put me to over 1/4 tank, ran good for 10 more minutes. Limped home at 45mph. We have changed the MAF sensor, fuel filter and checked vacuum lines. Codes given said fuel mixture to lean.
PO171, PO174, Misfire on Cylinders 5 & 6. Any ideas what it could be? My next move is to check EGR valve or is this a waste of time?
Avatar
Leabea1@live.com
April 17, 2008.




Them first two are lean codes, use some carb cleaner and spray around the intake manifold to see if there are any leaks. The idle will change when it sucks in the fluid.

Are all of the codes current?

The V6's with plastic manifold can develop a vacuum leak at the seams get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs!

That will take care of the 171 and 174 the 176 and 177 are the fuel composition circuit. Maybe some bad gas, or a problem in the sensor or wiring.

Merlin2021
Apr 17, 2008.
Codes 176 and 177 showed up before MAF was switched. Waiting to see if the truck has the same problem today on his ride home. Will post any other codes if the truck malfunctions again.

Tiny
Leabea1@live.com
Apr 17, 2008.
Can you clear the codes? Do that then start again!

Merlin2021
Apr 17, 2008.
Okay, here is the saga continued.
All codes cleared. Have changed the Throttle Positioning Sensor, MAF, Spark Plugs & wires. The truck still acts like it always has. 35 minutes into the drive going along at 70mph, engine stumbles, drops down to 20 mph. If you try to floor the accelerator truck will die. You have to keep a steady low pressure on the gas pedal, until you get back up to 50mph. WHAT CAN CAUSE THIS! Truck will be fine after you turn off for an hour and then after warming up again for about 30 minutes it starts all over. HELP. No codes showing when this happens.

Tiny
Leabea1@live.com
Apr 23, 2008.
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Merlin2021
Apr 23, 2008.
Did the fuel pressure test. Pressure is constant at 63. Okat there. When this happens the O/D light starts blinking, but no codes are in the computer. Is there a sensor at the transmission that would cause the engine to run in this " safe Mode"?

Tiny
Leabea1@live.com
Apr 24, 2008.
Here's a TSB tidbit I found on it...200-2003 Rangers Sables, and Taurus...CMP synchonizer problem 3.0 engines?


http://www.2carpros.com/forum/automotive_pictures/62217_Bucka_1.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_Buckb_1.jpg


Merlin2021
Apr 24, 2008.

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