Hello, I have a 97 Ranger W/4.0 Auto EXt Cab 4x4 with a serious engine miss. It started out as a slight vibration at idle, and then rapidly got worse until it was missing all the time. I replaced the intake gaskets, air/oil filters, plugs/wires,and used many diff kinds of injector cleaners but still no change. I was told that the valve guides were burned out. I did a comp check and all cyl were at 115psi except for the #3 at 130psi. The #3 also burns darker and gets hard dark deposits on it. If the guides were bad would it not smoke at start-up, or atleast use some oil? It never uses oil or smokes. I am in dire need of some help!! I can try to give whatever further info you may need.TIA.. Kevin

 

Welcome to FTE!!

I would determine which cylinder is missing. On my 94, there are diagnostics that enable a person to find a weak cylinder; fuel is sequentially cut off to each cylinder and the drop in rpm is noted. Not much drop = weak or dead hole. I'd expect you can do this on a 97. Once you have that, check the plug wire just for good measure. Next, I'd inspect the electrical connection on the injector for damage, corrosion, etc. Next, I'd swap the injector on the weak cylinder with one from a known good cylinder and run the weak cylinder test again. If the weak cylinder is now the one with the suspect injector, you have a bad injector. If it's the same cylinder, you need to determine if the injector is getting a signal from the ECM.

From what you have said I don't think you have a valve guide issue. Let us know how you make out on this.

 

Thanks for the reply. How do I do the diagnostic check to figure out which cyl is the dead one? I thought the one that was giving me trouble would be the #3 with 130psi comp and has the deposits on it. But I don't know for sure.

 

Welcome!

Is the Check Engine Light on? Such a serious miss should be generating a trouble code and a corresponding CEL.

 

The diagnostics for my EEC-IV are described in the book with my code reader. You have OBD-II and I'm not sure on that one.

 

The jerk that told you to replace the valve guides needs to be left out of any future plans you might make!
I don't know what is makeing your ride miss but I DO KNOW it is not the valve guides! If it was using some oil maybe the valve SEALS could be replaced, but the guides last till a complete rebuild.
Did you check the compression with all of the plugs out?
I'd suggest setting the idle to 1000 or so and pulling the wires one at a time to see if one of them does not make a difference when pulled... This could tell you a lot.
Big Jim

 

I agree with Rockledge, get the error codes scanned....

 

Hey thanks for the reply. It doesn't have any trouble codes stored. But what I did is pulled off the plenum and did an ohm check on all injectors and they were all at 14.3 except for the #3 cyl and it was at 15.4.... Does this sound like the #3 injector is the culprit? I ordered up a new one in hopes that this is the problem. I don't know what the tolerances are for them, that is why I ordered the new one. I told the guy who said it was the guides that he was wrong and then he said that it more than likely would be a fried cyl!!!!! He is supposed to be FORD certified!!! Anyway thanks for the advice.

 

See my earlier post about swapping injectors.

On edit:

By paying careful attention to the gauge while doing the compression test, you can determine if you have weak rings/cyl wear or a burnt valve. However, this is probably irrelevant as your highet compression is on the dead hole.

 

First and foremost, thank you to all who tried to help me out, and gave me advice on this problem. I replaced the #3 injector today and yes my Ranger finally runs good. It runs better than it ever has. I paid that guy $200 just to tell me that I needed to replace my heads or maybe get a boneyard engine!! For $67 and about an hour I fixed it myself. Just goes to show if you want it done right you got to do it yourself. And again thanks for the help.