zap

I know a good mechanic in Austin that knows the 4.2 better than any Ford tech. In fact, he knows most 97 and up Ford better than any Ford tech and charges way less than Ford ever would. But your more than likely not in Austin so that isn't really much help to you.

97Shozt

Naw, I'm pretty far from Austin =(

Any idea if a clogged cat can cause misfiring on one cylinder?
It makes more sense to me that it would affect 3 cylinders at the same time.

zap

Yea. Like I said. Try pulling the plug out and seeing if it spits gas or not when you try and start it or get it running (just don't let the manifolds get hot, seen fires start that way).

97Shozt

Won't the fuel be in a gaseous form? Mixed with air?
How will I know if there is fuel in the air coming out?
The fuel is mixed with air in the lower intake and is vacuumed into the cylinder isn't it?

Or am I absolutely 100% confuzzled?

zap

The vapor should condense. But if you see a bunch of liquid coming out, you have issues. Helps if the engine is cold when you do this.

97Shozt

Ok. I will give it a shot.

I'm about 90% sure that the lower intake isnt cracked though. I had a coolant leak before coming from cracked heads, I replaced them and coolant level has not changed since.

I will let you know what i find out.

zap

Mine cracked at like 94K miles. I got lucky because it cracked on the outside where the coolant elbow meets the manifold. Got it to the shop before it cracked further and began dumping in the manifold. A few guys I know have actually bent rods and completely destroyed the heads from the manifold cracking internally. It's hard to sale the 4.2's in my area because everyone knows how unpredictable and how expensive a cracked lower intake manifold can be. Once you have one and want to sell it, it's almost easier to put a different engine in it an keep driving it.

97Shozt

Holy crap. Hope mine isn't cracked.
I would be piiiisssssssedddddd off.

Why did a cracked intake bend rods?

zap

There is a pressed steel fitting in that manifold that carries coolant for some reason unknown to me. It's about a 1/4" id tube that feeds it from the water pump. The steel and aluminum expand and contract at different rates. Eventually the aluminum gets stressed and cracks. If it cracks internally, it begins dumping coolant into the manifold which feeds it into the engine through the intake ports, past the injector rails, and down to the valves where it enters the cylinders and hydrolocks the motor. That's one main reason I say pull the plugs and see what comes out when you run the starter.

97Shozt

Ohhh. I see.
I thought you meant something else other than hydrolock caused that.

If I had a cracked intake would I be losing coolant no questions asked?
Or is there other symptoms to look for?