Poor idle/stall/service engine light

[Berg9]

Hi,

Just found this site and looks very interesting. Perhaps as start, someone could help me out with a pretty urgent problem.

The story goes:
My 99 V6 4.0 E (35k miles)had the service engine light come on. Checked the code and got a 151 (right bank o2 sensor)

Also, it started idling erratically between 700 and 450 revs, even sometime stalling.

Took it into local Ford dealership, who ran some diags and subsequently replaced the inlet manifold gasket (diagnosed as an air leak from this gasket)

Picked it back up, but after 10 miles the light cam back on and poor idling continued. Long story short, after several visits to Ford, they suggested that the only solution would be a trial and error campaign, stating with replacing the O2 sensor, then MAF and so on.....

Since then, I have replaced the MAF myself and triple checked all hoses and connections for leaks. However, I still get the engine light on virtually every day and the idling seems to be getting even worse, now to a point where it regularly stalls. (the code is still 151 and also once a 174 - lean mixture)

Next step (have ordered) is replacement of the IAC (idle air Control Valve), in the vain hope that this may solve the problem. Also dropped in a can of injection system cleaner to clean out the Fuel injectors.
Also removed the inlet manifold and added gasket sealant to the manifold gasket to be absolutely sure.

It is very hand to get some Ford support here in the UK as the Explorer is not a very common car and their experience and knowledge is very limited.

Can anybody help me out here ?? (Desparation setting in now...:frustrate:

Many thnx in advance

 

[Howard]

Firstly Welcome to another UK owner.

I am well aware of how hard it is to get support for our x's here. I was going to sugest the IAC but you have already ordered one. But I think it is alikely candidate. You could try cleaning it and if you do a search you'll find the cleaning thread. Also after cleaning you can re-set the computer. Lets see what happens with the IAC.

 

[Berg9]

Actually forgot to mention,but the IAC when disconnected reads a closed circuit over the two connector legs..i think it should be betwee 6 to 10.5 ohm at that point ??? Also, the IAC valve itself stays slightly open when you remove it a look inside. I would have though it should be closed ??

Cheers

 

[Alec]

I have a feelings it's the IAC, but could be wrong.

 

[Howard]

Yes it should be closed so therefore it's stuck. So lets see what the replacement does.

 

[robswe01]

I got about the same idling problem with my -97, but I also lost some of the engine power.
Just like in UK, it's hard to find knowlege about American Fords here in Sweden, so please let me know if you find the problem with your car.

 

[Berg9]

Well...so far, so good .....replaced the IAC last night (got it in record time from the states - 4 days and for ½ the price of a UK supplied)...the idle has been rock solid since and the whole car just somehow seems to run better/smoother. Just hope I do not get the engine service light back on again....

Best rgds

 

[bhults]

Berg--Welcome!

My 95 began to idle irregularly...I paid no attention to it at first. Then one night I took the truck to go to the gym (it was cold, hadn't been driven all day)...and it did NOT want to go! The more gas you gave it, the more it sputtered! It finally began to cooperate, and I made it to my destination and back. I, also, had been experiencing an interemittant check engine light. After removing/cleaning/replacing my IAC, I have yet to see the problem surface, and have not seen the CEL since! I think you made the right move. Take care!

 

[Berg9]

bhults...

Many thnx.....well, it's been 5 days now and all is still well and no sign of Engine check light...fingers x'ed

Cheers

 

[jeremism30]

I used to get the engine service light from an old gas cap.

I'm not saying that’s the cause, but perhaps two different problems.

I have had the same problem with the IAC in the past.

 

[Billy177]

if you get a cel again it is because the iac won't throw a lean code it is your throttle position sensor