I've been discusing my f150 troubles with some Ford techs over at Stangnet and a couple of people told me this was a good forum to enroll in. My trouble is this...my truck runs rough, and I was told the culprit could be the #4 COP due to a leaky heater hose. I'm getting a scan tool this week to make sure since the COP's run a bill a piece. What I'd like to know is, as a prevent measure, what is the fix for the leaky heater hose above that COP area? Thanx.

 

Not sure, but think it's just changing the 'weak' stock hose clamp for 'screw-type' clamp. I don't have the problem, so I'm trying to remember an earlier post??? Dan

 

I'm sure someone will correct me if I'm wrong, but I think the Service Engine Soon light needs to come on before there will be a fault code stored in the system.

At any rate, I think all you have to do with the clamp is to tighten it or replace it. Mine never leaked, but if it did, I'd assume that there would be evidence of leakage that would be visible to the naked eye.

Do a search on "rough idle" to find a whole slew of possible causes and fixes.

 

So far I've cleaned the MAF, changed the plugs, fuel filter and O2 sensors. Everything needed to be done again. I reset the computer after doing this, but it's still running like crap and getting worse. Like it's almost on 7 1/2 cyl. There isn't any residue, and I think the clamp that's on there is the screw type. Just have heard that it's a common problem, the heater hose leaking and shorting out the #4 Cop. Thanx for the help. Keep it coming.

Oh..at first it didn't have a rough idle...just when I put on the gas. It's slowly trickling down to idle though, like something is slowly dying.

 

The symptoms started out when you were stepping on the gas but it idled normally at first? Then it started to idle rough as time went on?

What year is your truck and how many miles?

 

I just fixed my #4 coil problem a few weeks ago. What my engine was doing was misfiring almost every time I jumped on the throttle a little bit, for example, when passing someone. It happened more often when the A/C was on - more load on the engine, I guess. The check engine light would come on and blink as the hesitation was happening but since it only happened when I was on the pedal it would turn back off about 10-15 seconds after I let off the throttle. I happened to be in the shop for something else and asked them to read the code for me. They said it was a "random misfire" which was not associated with any cylinder in particular. After a post or two and some good advice from here I went in a checked the #4 coil.

Well, that's what it was. As soon as I cleared the path a bit to even get a peek back there I could see the gunk (coolant+dust mixture) had accumulated at the bottom of the heater hose. Yep, $100 for the coil from Ford but it fixed the problem.

As far as the clamp, of course the nut was facing the firewall so I could barely touch it with one finger let alone get a tiny ratchet in there. (I have big hands) I wanted to loosen it figuring I'd spin it around then be able to tighten it properly. Since I couldn't do that I took another hose clamp, opened it up, put it on the hose in front (closer to the firewall) of the existing clamp and tightened it really, really good.

This "should've" worked well, but I'll know better this winter.

HTH

 

Aycardus, great post. Gives more detail about symptoms leading up to the #4 coil problem. I'm sure you helped a lot of people today.

 

Thanks, Dennis. I've found a lot of useful info here so I'm just trying to give some back.

BTW, I believe your correct about the CE light and storing the code. I also remember reading in here somewhere that the problem has to continue for some 2 minutes before it gets stored with more detailed info. (?)

This would make sense in my case since the code was stored as a "random misfire" even though it definitely was originating from the #4 cylinder. The hesitation only lasted a few seconds while I was on the pedal a bit so I guess that's why.

 

My truck ia a 98 and it has 118337 miles. My truck was displaying the excact same symptoms as Aycardus. I found the problem though. I didn't bother waiting for the scanner that I ordered. I just started pulling the COPs one at a time and measuring the resistance on both the primary and secondary sides of the coil. The number 6 coil had infinite resistance on the secondary side, so I swapped it. Truck runs like a champ. I think they redesigned the COP a bit, I like it, it seems to make more contact with the plug now. I think the parts guy at the local dealership felt sorry for me so he knocked about $40 off the price of the coil. Some guy in Canada told me on Stangnet that he paid $160 for the coil, and another $150 for installation. Mind you that's canadian, which is about $220 us. Man, glad I did it myself.