I recently replaced all 8 plugs in my '01 4.6 with 8 Motorcraft plugs. Got a set of new COP's from Global Automotive. I had some problems, so a mechanic (a trusted one, if you can believe it) said that becuase it had misfired, (I had a miss in #4) that the cats may be clogged. Before I invest any money in a Magnaflow exhaust, I wanted to get some feedback. I just cleaned the IAC and the pickup seems to be back to where it was when I bought the truck. It is not throwing any codes, but still hesitates between 35-45 MPH. Like I said, the HP feels fine. Is there a way I can check the cats without taking it anywhere? Any help is appreciated.

 

sounds like the mechanic doesnt want to go back over all the plugs, It ran fine befor the plug change, and had a miss after... thats not the cats. go to that #4 plug and wiggle and push down on the cop. chances are its just not making good contact. Ive had that problem many times.

 

It still had a miss before the change. I was actually the one who changed everything in it. I took it to him b/c it still has a misfire. It doesn't seem to be as bad, but it is still there.

 

hmm possible the injector.... switch that injector with a new one, or with a different one, and see if the miss still happens, or if it starts missing on the one you switched it with.

 

I was told once that a way you can tell if your cats are gone is by how hot the exhaust is when you rev the engine. Basically you start the truck and let it run for a couple minutes. Then you have someone rev it while you have your hand a little ways in front of the tailpipe. It should be hot but not too bad, but if the cats are plugged then it will be VERY hot and youll move your hand away pretty quick. Its not the greatest way to test but it seems to work.

 

Yea, I took out my cats thinking they may be getting plugged after 220,000 miles on my 98 . I was surprised to find that they were pretty clean . I put 2 new ones back on - but just two instead of four and like the way it sounds and pulls.

 

Appreciate the help. I never even thought about the injector. Of course, when I got in the engine today, I noticed the little clip that connects to the COP seems to not be in there. The clip won't snap onto the COP like it is supposed to. Anybody got a fix for that? I will still test the cats, using the hand test built54 said. Right now I have a feeling that little clip that attaches the wires to the COP may be the problem. I don't know how in the hell that thing came off. of course, if something is going to happen, it will happen on this truck.

 

Sorry, it was Rdhammer that told me about the "cat test".

 

And while I am at it, my idle speed seems to be at 600. Shouldn't it be at 650? I am sure this problem with the COP clip has something to do with it.

 

COP'S don't have clips ??? Are you talking about the electrical connector itself? Your idle prob is an IAC problem - low idle means it's stuck tight and not moving at all. You need to clean it. Free the mechanicals up inside the sensor w/screwdriver or small needle nose pliers. A broom handle knocking on the housing will do it in a pinch , but it still needs to be cleaned and serviced the right way to run right.

You must not have worked in WD40 and free'ed it up. It does no good cleaning without that process.

Idle should be @ 750 RPM.

 

That would be it. It is on the connector that snaps (locks) onto the COP.

 

I will get that IAC cleaned up. Any ideas about the clip though?

 

It won't be able to convert the low voltage PCM signals to high voltage pulses correctly without that pluged in all the way.

If it's broke , you can solder the wires directly or just tie it together somehow and order a new connector.

 

Do you have a fix for that? Since the clip slid out and there is no crack or anything, I might be able to purchase that POS plastic piece. Either that, or visit a junkyard and then splice the connector. But being that close to the engine, I don't know how smart that would be. I figure if anybody knows, you would jbrew.

 

Sorry JBrew. I didn't see the bottom of that last post.