It's the only thing to worry about. All of the 4.2's major issues have been related to the cracking of the lower intake manifold and the gaskets. It would leak, unless you can find a visible crack else wheres. That is the only reason it has to crack.

 

So what you are saying is that this is going to cost me a **** load of money...
damn.

I really should have done more research before I bought this POS

 

Hopefully it's not cracked. But if the gaskets are gone, that's like 6 or 7 hours of labor alone. When I had to replace my lower intake manifold, I couldn't afford a new one. I just did not have the money to get one so I ended up getting one out of a junkyard. Only problem with that is it's a real gamble. A used one could last 5K miles, it could last 200K miles. Most people love the 4.2, have never had problems with them. Others, such as me and you have nothing but problems with them. I'm trying to get rid of my engine as quick as possible to go to a 3.9L I4 that I don't have any trust issues with.

 

Its time that someone steps up and tells their opinion of the 4.2L engine. I am the original owner of an 02 with 218K on the odometer. I have had issues with this truck, but nothing compared to the whining that is being spread about intake manifolds and other failed attempts at repairs. Enough said!

You are having a code indicating #1 missfiring, and asked about the cat affecting only one cylinder, why not the whole bank? I agree, concentrate on only that cylinder, but remember, the coil has six towers with three signals from the processor (PCM). Two plugs are firing at each command. One cylinder is on compression stroke and the other is on exhaust stroke.

I don't know exactly what you are feeling during acceleration (engine miss), nor do I know the history of your truck, keep focused on the issue at hand and proper results will be obtained.

If you would like to talk further send me a PM.

 

Zap- I replaced the gaskets from heads up less than 2000 km ago so I am fairly confident it's not that.

Bill- I am on the mobile app right now but I will pm you a little later.

 

I'm just really unlucky with V6's. lol Every one I've gotten into has had major problems before they even had 100K miles on them.

 

Hey all
I have a 97 4.2 with 60K original miles on it. I started to have a misfire fault on #4cyl. I replaced the same(plugs, plug wires,coil pack, I checked with a boroscope inside the cyl and found nothing, no carbon deposits, all appeared fine. compression was at 180psi. I removed the upper intake inspected the intake chamber, found no carbon and the intake valve looked clean. I swapped out #4 and 5 injectors and still have the same misfire Po304(Number4 cylinder) I placed a noid light on the injector and it did light up and as I increased throttle it grew brighter. I am at wit's end. I'm guessing ECM issues but am not sure. this issue seems to be common. Any ideas I think I covered everything I can think of.......

 

Hey cletisp97, send 97Shozt a PM about your issue, he just sent me a PM and he has his repaired. Talk to him directly as to what was done, he is an OK guy and I am sure he will be willing to share his experience.

 

Whoa... Good catch bill... Ive not been around much either..

 

Hey cletisp97 sorry to hear about your troubles. Hope it all works out soon.

Can you describe the conditions to which your truck is misfiring? (idle, acceleration, load, ect ect)

Also, did you use motorcraft plugs/ wires/ coil?