Hello to everyone here. I have a ranger 1999 that threw a code 1151. I brought it into the shop and they started by replacing all spark plugs and wires. They cleared the code and after 30 minutes of driving, it threw the same code. I also notice when stopped at a light, the engine (sometimes) runs real rough. Like it wants to shut off, but doesn't. What is wrong with my ranger?

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Joe Sticklin

Ford Ranger 3.0L 2x4wd flareside 1999

My Ford CD only goes back to 2000, but here is what it shows for your code:

P1151 - Lack of HO2S (heated oxygen sensor switch)-21 Switch, Sensor Indicates Lean A HEGO sensor indicating lean at the end of a test is trying to correct for an over-rich condition. The test fails when fuel control system no longer detects switching for a calibrated amount of time. See Possible Causes for DTC P1130

The possiible causes for DTC P1130 are:

Electrical:
Short to VPWR in harness or HO2S
Water in harness connector
Open/Shorted HO2S circuit
Corrosion or poor mating terminals and wiring
Damaged HO2S
Damaged PCM

Fuel System: Excessive fuel pressure
Leaking/contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system

Induction System:
Air leaks after the MAF
Vacuum Leaks
PCV system
Improperly seated engine oil dipstick

EGR System:
Leaking gasket
Stuck EGR valve
Leaking diaphragm or EVR

Base Engine: Oil overfill
Cam timing
Cylinder compression
Exhaust leaks before or near the HO2S(s)

Hope this helps...

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'20 Ranger Lariat FX4 Oxford White

Thank you for your input. I did have the spark plugs and spark plug wires replace by a shop. I also replaced the EGR value, cleaned the MAC and cleaned the IAC. The truck doesn't seem to idel rough all the time. I notice it only idels rough after it has been running for awhile, like driving to work or the store 20 MILES, TURN OFF, then when I start truck back up it will SOMETIMES idel rough. I also noticed the code 1151 shows up sometimes after 50 to 100 miles of driving, random, and after a trip 500 plus miles and back, it threw a cylinder 6 misfire. Please point me in the right direction on what I should check next. Could the throttle position switch be bad or could it be the actual O2 sensor? Would that cause these random problems? Please help the confused.

__________________
Joe Sticklin

Ford Ranger 3.0L 2x4wd flareside 1999