I have a 98 expedition with 72k miles or so. I have the engine light on with P0174 code,
Fuel filter has been changed, EGR has been changed, injectors cleaned all at the suggestion of dealer.

Still comes on, when the problem occurs there is severe pinging, I mean severe. but other times there does not appear to be a problem. I can floor it get upto 95 MPH and it seems fine,

Strange thing is there appears to be a sensitivity to outside temperatures,

When its mild its worse than when its really cold.

Engine temp seems same as normal. could it be the air intake sensor..If so why not lean on both sides,

Which is the left side any way, the passenger side or the Driver side.

If it s the PVC hose like a lot of post suggest, why not both sides. Actually I checked the PCVhose this afternoon it seems fine, I removed the PCV valve with engine running there is plenty of vacuum beneath it.


Seems to me that the computer is telling the injectors to weaken the mixture or that the air regulator is sticking although I have greased it and it appears clean and working ok.

 

For what its worth, I cleaned the MAF with a cue tip dipped in alcohol, I was surprised how much black came off it even though I had cleaned it previously with carb cleaner.

I beleieve the main trick was draining the computer with the headlights on.

Since then almost two weeks we havent had the light return nor do we get the ussual pinging under load.

Thanks you all for your adivce.

 

That's great! Thanks for the update.

 

Hello, sorry if this question is DUMB !!! but

what do you mean Drainig the computer with the lights on ????

 

Disconnect the battery then turn on the headlights. This seems to help drain any "residual" power stored in the electrical system.

 

I have a 98 expi also and whatever I do, I can't get rid of the pinging.Its worse in the winter than in the summer which is backwards.I did however flush the cooling system real good and the pinging did get better.Did you pull the upper intake off and really clean it well.I had to actually pull it all apart to get it totally clean. Those ports get clogged.

 

My pinging has gotten better and I have been here looking for answers. First, I had the injection system cleaned at Goodyear, may or may not have been a great idea but I did it. Next, I installed a new battery. (Disconnecting the old battery had not done the trick) Over the last three months I have had noticeably less pinging, in fact, if I let it warm up for 2 minutes in the morning I don't get any.