Krack499

iTrader: (1)

Any codes

Fordfan2006

you should make one on changing the CHT without taking the intake off

Deepoutdoors

I have a 97 f-150 4.2 liter that runs perfect when the fuel tank is toped off but when it drops down to about a 1/4 tank it will no longer idle when you first start it. What I have to do at this point to keep the engine running is manually advance the accelerator by pressing on the peddle. I can then operate the truck by keeping one foot on the accelerator while breaking with the other. Once the truck warms up it will then idle on its own but in a surging manner that oscillates between 700 and 400 RPMs it will continue this rhythmic fashion until it eventually dies.
Once you get to the gas station and fill it up, It will start right up and will idle perfectly.
Any Ideas as to what could be causing this? One other problem it is having relating to filling it up is that once the gas nozzle cuts off; the truck can still hold another 5 gallons. I don't know if that has anything to do with the 1st problem or not.
Any help would be greatly appreciated. There are no engine codes....

MCpllabelle

Sounds like a venting issue. The charcoal canister is most likely plugged up.

03heritage4x4

3) PCV (Positive Crankcase Ventilation system)




good info on the subject, but my question is about heated pcv. my truck has a heated pcv but the cost difference is astounding. $85 vs $4 for a non-heated pcv. can I use the non-heated pcv in place of a heated pcv without any loss of performance or possible damage to the engine. 5.4L

Jbrew

That's very much untrue. Once you do at least a little minimal research yourself, come back and apply it. I mean , if you can't so much as get the info you posted correct, just how are going understand anyone attempting to help you. I'll help, do all the time, but come on... Perhaps taking it in for service is your only option. Guess we will see.

03heritage4x4

just what part is untrue about what I posted?

johncoby

GREAT info!
Maybe you can help. I have a 1999 F150 V6. My temperature sensor, the one in the head, was replaced. Even with the new sensor my temperature gauge over time (20 minutes on the highway) will creep into the red, but the engine is NOT actually hot. It runs normal. The scanner reads 230 which I believe means an open circuit.

To compound this.....my Intake Temperature Sensor was giving off a -40 (open circuit) but would go away after a few miles. The sensor was replaced but I still have the problem with P113 code.

And...my gas guage is now acting strange.

I wondering if these point to a problem with the PCM?

jprevat

iTrader: (1)

my heated pcv was about 15 or so from Amazon for Motorcraft. On that note a pcv in these trucks needs to be Motorcraft.

jprevat

iTrader: (1)

I'm thinking that or the harness itself. Pull your battery cables then unbolt the harness from the pcm on the passenger firewall under the hood. Check the pins for water intrusion or corrosion.