Hello - I posted a message a few days ago regarding my Explorer's rough idle/engine stall and received some responses providing good suggestions...appreciate it very much. Since my original message, I stopped by AutoZone and had the codes pulled. Here's the scoop.

1997 FORD EXPLORER 4WD
6 Cylinders 245 E 4.0L EFI SOHC

Codes:
P0171 - lean code bank 1
P0174 - lean code bank 2
P0304 - misfire in cylinder #4
P0305 - misfire in cylinder #5
P0306 - misfire in cylinde #6

Symptoms:
Very rough idle when I start in the morning (temps in the 30s). After the engine warms up, everything seems fine, but until that time the idle is rough and inconsistent...reving up and down and usually sputtering out. I find myself applying slight pressure on the gas to keep it 2k rpms until warm, otherwise it will quit and require restarting. Again, it only does when the temps are cold and the engine hasn't been running for a while.

Any ideas based on the codes and symptoms described above? I will be able to leave my Explorer with a family friend who is a mechanic. I normally take the parts and he installs at a very reasonable price. While he has it, I would like to go ahead and have him take care of all of the possible solutions (e.g., manifold gaskets, maf sensor, etc.).

Thanks again for your help...I'm grateful for the posters who are willing to share their knowledge.

Steve

 

I had the same problem & codes on my 97 Ranger 4.0 & did all the parts changing that a person shoulkdn't do in the first place. In the end it was the gasket between the fuel rail & the intake manifold. It is a hard compressed paper type gasket not unlike a header gasket. You will also need new orings for the injectors and upper plenum oring type gaskets while you are in there. I fought this for quite a while before tearing into it one day. The gasket had beed sucked in on the drivers side rear of the intake by the firewall. The factory designed it with a long space between bolt holes. I could only find the gasket at the Ford dealer. Like 12.00 if I remember correctly. I would try spraying some fluid back toward the firewall & see if it shows up. Later, Jay

 

did you pull your plugs ? is there any build up on them ? are you losing antifreeze ?

 

Since your 4.0 engine is the SOHC version, it's probably the lower intake manifold o-rings leaking. I'd replace both the upper & lower intake manifold o-rings. Those early SOHC engines were bad about doing that.

 

Same advice as before:
You have a vacum leak. Start with diagnosing where it is with the TB cleaner then go fix it!

 

71 and 74 I just went through. I went though cleaning the MAF, plugs, wires, O2 senseor and then started looking for a vacum leak.

I found the rubber elbow below the IAC to have 3 holes in it. I read a thread on the expedition list and someone on there said they have changed 75 or so.

I wish I would have started there but am happy now my 01 sport trac doesnt stall when the rpms at idle dip just below 1000. I was looking to change the pcv valve and ran into the holy elbow. The hose from ford was 35 bucks but a short elbow and one hose clamp from advance fixed me up right for less than 10.

 

It ended up being a timing chain problem. The timing chain tensioner was so worn out, it caused my chain to jump sprockets. WARNING ! Let an experienced Ford mechanic do the work on this. I had the timing chain set back into place 3 sprockets and had the lifters timed back in place, but, for some reason, while test driving the truck which ran beautifully, the chain came loose and tore up the gears. Could have been a broken or loose chain or didn't torch down the gear properly.