The cats on my truck have just about bit the dust. Has anyone ever replaced the factory cats with universal ones? The truck is a 97 4.2 4wd and I was curious if these would throw a code or not. Thanks!

 

They may or may not throw codes. I think it all depends on exactly where the rear O2's are located.

 

It has sensors behind the cats but they are far enough where fitment won't be a problem. Someone told me about the resistors from Radio Shack but with the heated O2 sensors I don't see how that would work. The factory style cats are crazy high so if nothing else they may just get cut off for now and see how that works out.

 

Cut off the all the cats, even the two small precats, get a set of magnaflow universal cats and call it a day. I'm on my second set of hiflows and I have never had them throw a code. the cats I got have an O2 bung built into them but you can get them without and just put the O2 sensor back in the original spot. Take your old cats to a scrap metal recycler you should be able to get some $$ for them to help offset the cost of the new cats.

 

going in the morning to have it done!

 

Well, put on the new cats and the CEL went off. The problem now is that when the truck sits for several hours and you try to start it the truck will fire off then die after a second or two. The fuel pressure is fine but it acts like it is running out of fuel. You can hit the key when the truck has been sitting and wait a second and try to start it and it will start just fine. Figured on a 97 an O2 problem would throw a code. I have ran 2 bottles of techron through it and changed the fuel filter along with a general tune-up. Any thoughts?

 

I'd clean the throttle body and IAC.

 

Thinking there is a leaky injector. You can hold the pedal down and the truck won't start but you can cycle the key on and off several times and it will fire off fine. Cleaned the IAC and the throttle body is clean. ran several bottles of techron through it and that hasn't helped. The problem started after i ran a bottle through it, actually. Be nice if there was a CEL on.

 

If you have a leaky injector, you can check for it by lifting the fuel rail keeping the injectors plugged into the rail, and put a piece of paper under the injectors. Turn the key on and look for drips.

Have you tried testing the fuel pressure with a gauge? Most parts stores have a gauge in their loaner tools and there's a port on the rail for connecting it.

 

I checked the fuel pressure with the vacuum hose on and off of the regulator and everything was normal. Next step is to lift the fuel rail and check for drips. 8-)