ROUGH IDLE. 2004 F150 Lariat, 5.4, 170K miles

3 months ago engine light. Rough idle, some knocking. Code P0022, Suggest replace Cam Sensor (Bank 2) Drivers side. Done engine light off and running fine.

3 weeks ago, engine light. rough idle, no knocking. Codes P0022 - Intake Position Timing - Over Retarded (Bank 2), Code P0171 System Too Lean (Bank 1).

Suggest replace VCT Sensor Bank 2. Did that and cleaned MAF Sensor with Appropriate Spray. Still a rough idle, not horrible, but rough.

Faulty Part? Removed just replaced VCT and put in a new replacement VCT. Engine light again. Still rough idle and pulls the same codes P0022 and P0171.

Any suggestions on next steps?

Thanks in advance for your help,suggestions!

 

You need to do a Relearn procedure after doing those repairs. Especially if your expecting to see a difference in idle.

This way, a new idle curve can be established based off new engine parameters.

 

Thanks J!

I'm not a real Technician/Mechanic, what is a Relearn procedure?

Sorry for the dumb

Please advise.

 

Have you recently done any work or modifications to the truck? Disconnected the battery or replaced for any reason?

Or, how long ago were the plugs replaced?

Reason I ask is if any of these things are so, then, you may need to do a TPS relearn procedure.

Anytime I do work on mine I just reset the PCM which will rest the TPS and go through a relearn procedure for the entire system that has "learned values".

The way I usually do it is to :

1. Disconnect the NEGATIVE - battery terminal.

2. Using a jumper wire of any size, connect one end of the jumper wire to the NEGATIVE - battery CABLE (not the post on the battery).

3. Connect the other end of the jumper wire to the POSITIVE + CABLE and POST (the positive stays connected to the battery).

This will discharge all the stored energy in the capacitors and reset all modules and allow you to let the truck learn your driving habits.

Very important steps though.

1. With truck in Park, with parking brake engaged, all accessories off and devices unplugged, start the engine and let idle for atleast 5 minutes.

2. With truck still in park, brake engaged, turn on the a/c, lights, and all other accessories. Let idle for atleast 5 mins.

3. With foot on brakes, shift to "Drive". Hold this position for atleast 2 mins (I always do atleast 5 here as well).

4. For the next few driving cycles, be sure to drive "normal" as the truck is learning driving habits, fuel curves, and shifting info.


This could help your idle issue. If nothing is broken, lots of times the values just need to be reset.

Hope this helps.

P.S. During this process, you will notice the truck idle fluctuating a good bit. This is normal as it is adjusting for the "base" idle positions under various load values, which, is why you do the steps as listed so it can properly calibrate.

 

Pasted from another thread where I gave same unfo.

 

Thanks Jamieat!

I will get jumper wire tomorrow and follow your procedure.

I will report back.

Thanks again!

 

As far as a jumper wire goes any piece of wire will work. Or, just disconnect both cables and clamp the positive and negative together with some pliers or anything that works and leave them as such for 5 mins or so and then reconnect positive first then neg.

Does same thing as jumper wire

 

Hi Jamieat,

Before I did the relearn procedure I remembered you asked about changing the plugs.

Since my engine has those skinny plugs that break off I really didn't want to think about them myself but I did do some investigating.

I disconnected the coil wires one by one to see if a change occurred in the idle or not. If the idle was affected I assumed it was good. I got 2 that appeared to give no change so I bought 2 coils and changed them out.

I then did your relearn procedure and then drove the truck for about 30 minutes in my normal driving pattern.

Idle has smoothed out, engine light is off and has stayed off after several additional driving cycles.

Thank you mucho! I think you solved my problem!!!!!!!!!!!!!!!

Kind regards,

BC