Intermittent high idle F150 5.4 1998

Definition of Diagnostic Trouble Code P1506 Audi: Closed Throttle Position Switch Does Not Open/Short to Ground BMW: Idle-Speed Control Valve Opening Solenoid Control Circuit Signal High Ford: Idle Air Control Overspeed Error (see P0507) Jaguar: Idle Air Control System RPM Lower Than Expected - B Bank Kia: IAC Valve Opening Coil Voltage High Lincoln: Idle Air Control Overspeed Error (see P0507) Mazda: Idle Air Control Overspeed Error Mercury: Idle Air Control Overspeed Error (see P0507) Porsche: Throttle Jacking Unit Lower Mechanical Stop, Signal Implausible Volkswagen: Closed Throttle Position Switch Does Not Open/Short to Ground Volvo: IAC Valve Opening Signal
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Definition of Diagnostic Trouble Code P1151 Audi: Bank1, Long Term Fuel Trim, Range 1 Leanness Lower Limit Exceeded BMW: Oxygen Sensor Heater Circuit Signal Intermittent (Bank 2 Sensor 1) Ford: Lack Of Heated Oxygen Sensor Bank 2 Sensor 1 Switches - Sensor Indicates Lean Jaguar: Lack of H02S-21 switch, sensor indicates lean Land Rover: Lambda control limit bank 2.Implausible signal/condition Lincoln: Lack Of Heated Oxygen Sensor Bank 2 Sensor 1 Switches - Sensor Indicates Lean Mazda: Lack Of Heated Oxygen Sensor Bank 2 Sensor 1 Switches - Sensor Indicates Lean Mercury: Lack Of Heated Oxygen Sensor Bank 2 Sensor 1 Switches - Sensor Indicates Lean Subaru: HO2S-12 Heater Circuit High Input Toyota: Coolant Path Clog Up for Coolant Heat Storage System Volkswagen: Bank1, Long Term Fuel Trim, Range 1 Leanness Lower Limit Exceeded
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Definition of Diagnostic Trouble Code P0302 Category: Powertrain Definition: Cylinder 2 Misfire DetectedNote: This definition of P0302 is applied to all manufacturers
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Definition of Diagnostic Trouble Code P0171 Category: Powertrain Definition: System Too Lean Bank 1Note: This definition of P0171 is applied to all manufacturers

P2197 - Oxygen Sensor Signal Biased/Stuck Lean Bank 2 Sensor 1
P2187 - System Too Lean At Idle Bank 1
P2177 - System Too Lean Off Idle Bank 1
P2195 - Oxygen Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1
P2179 - System Too Lean Off Idle Bank 2

I am not sure what your Mazda is, but from the sounds of it, both of your Oxygen Sensors are shot. Replace them both, or check for vacuum leaks. It may be a good time to inspect and replace the PCV Valve and PCV Valve hose, too.

need to put it on a smoke machine to check for vac leak if no leak sound like egr valve sticking open

OK. Since you have had so much trouble lets check the dealer for an updated software calibration for the PCM (power train control module). Once we're sure there is no "fix" here lets talk about "lean" engine conditions. Lean means one of two things are wrong with the air fuel mixture (ideally 14.7 parts air to 1 part fuel). 1. Too much air -or- 2. Not enough fuel. If you access to a scan tool we need to look at fuel trims. With the engine warm look at this data on the scan tool. You have a "bank 1" and "bank 2" fuel trim data. Additionally, each bank has a long term and a short term value. With the Engine hot and at idle add the LT and ST trim value for bank1 and write it down...do the same for bank2. Repeat this step, for EACH bank with engine at 2500 RPM in park (hold at 2500 for at least 30 seconds so trims update). Now, you have the total trim values for each bank at idle and at 2500 RPM. What should the values be? Total trim +/- 5 is good, +/- 10 borderline any thing greater is code setting territory. If trim numbers are high at idle and in range at 2500 rpm you have a vacum leak behind the mass air flow sensor. Or a faulty MAF. Pay particular attention to the air inlet hose clamps behind (between MAF and engine) the MAF. Also use ford parts only.

Have you tried replacing the throttle positioning sensor?

see if catalyc converter is clogged it will make a car idle and run bad

How many miles are on the car? It could be one of three things.
1. Check vaccum lines running to the valve covers. The rubber nipple that connects to the valve cover sometimes gets a hole.
2. Could be 02 sensor depending if its lean on bank 1 or bank 2.
3. Also check DPFE hose's. Located on back of motor running from EGR valve exhuast tube.

fuel pump is going out causing the truck to run lean and miss

the idle air control valve is responsible for engine idle.
this is a common failure on ford's. but I don't think yours is bad because it does idle high befor it dies.
you stated you had codes p0171 and p0174 these are lean codes for bank one and two, you said you found a vacuum leak and repaired it, the vacuum leak was mostly likely the cause of the lean codes, however the pcm has calibrated the fueling stategy for this lean mixture, what you need to do is erase the KAM "keep alive memory" this is done by unhooking the negative battery cable for 60 seconds, this is the only way to erase the KAM the $6000.00 machine I use wont even do it.

once the KAM is clean the computer will go into a relearn state and all operating values will be adjusted for the vehicles current condition, during this relearn session the vehicle may have some driveability issues (low or high idle, stalling, poor fuel economy) the relearn should complete within 10 minutes of idling and then 10 minutes of driving.

good luck and keep me updated

wesleyschacht@hotmail.com

The lean condition is caused from the upper intake gaskets and isolation bolts not sealing properly due to time and poor sealing qualities from the factory ther was a service bulliten for this through ford to replace the gaskets,bolts,vaccum line,and lh side valve cover for this concern the oil was getting onto the rubber contaminating it causing a vaccum leak. If you never had the tsb done i would start there, also if there is high milleage on the vehicle i would also clean the maf sensor and resedt kam.