4.2L f-150 exhaust

[medwards29]

ok so im in the process of fixing up my trucks exhaust. The story is that my cats were clogged and caused my EGR tube to break off of the manifold.
So my quick fix was to take the cats off, hollow them out into straight pipes and stuff the EGR tube back into the hole. Well it wasn't as simple as it sounded, lol. the manifold bolts connecting the y-pipe snapped off, YAY!! And the EGR tube wouldn't stay in the hole so we crimped it down and help in down with a water line gasket out of an old Freightliner! lol then i put it all back together and had major leaks, but thats just details right?

Anyways now im fixing my leaks by drilling out the manifolds the right way and inserting larger bolts that hopefully wont rust into oblivion and installing brand new EGR tube. Of coure this day of work didn't go well either. I managed to break a stud on cylinder #1 (1st one on passenger side)!! So what should i do? Put the manifold on disregarding the stud, or do I try taking the broken stud out? There is about 3/8" of thread still exposed on the stud so welding a nut to the end s possible, but I ain't got a welder. Will the manifold leak badly if I leave the stud alone?

 

[medwards29]

I also have a flowmaster i can throw on it, will it be too loud with straight pipes behind it?

 

[rjjp]

First I would try to grab the stud with vise grips, Then easily work it out with LOTS of penetrating oil (I use JB 80, never had luck with PB Blaster) then go from there. The heads are aluminum so be careful if you have to heat them. Yes it will leak if you leave this stud alone. Also I would put the flowmaster on it, a straight piped gasser just sounds bad unless it's a race car, in my honest opinion.

 

[Diesel_brad]

As stated above. Get the broken stud out.

Dont put a flowmaster on. I had one on my 97 4.2 and it sounded like a HONDA, i hated it

 

[medwards29]

ok so i drilled out the manifold bolts that broke off so the y-pipe could connect correctly, and I just left the stock muffler on because i have made a cut in between the y-pipe and the muffler so i can change mufflers if i want to later. Also I left the stud where it was and it hasn't leaked yet. Now if it does start to leak i can just simply pull the tire off and the wheel well cover and drill out the bolt with a cobalt bit and replace the stud. Now i am waiting on a new EGR tube and she'll be all finished. I put it all back together this way cause time was against me. But now i have it all set up so i can change mufflers and drill the stud out in an hour or so when i get a chance. I started it up and other than the EGR tube hole in the manifold, it sounds pretty quite around y-pipe and exhaust is flowing really good out the muffler. yay! I watched a video of a flowmaster 44 series on a straight piped 4.2L and it was the best sounding one yet. So I might go with it. Regaurdless the motor will be louder than the exhaust cause its a Ford, lol.

 

[Diesel_brad]

Why did you even ask about the stud if you are not even going to take the advise that was given to you about it

 

[medwards29]

we tryed everything, vise grips, jb weld, welding a nut on the end of the stud to ry to break it loose, and we just stopped before we drilled cause we didn't have time to do it.

Now it doesn't leak as far as I know, but now I got a mass airflow sensor code, and cylinder 3 is misfiring. I checked the plug but it looked ok to me, no carbon build up, not broken parts, no corrosion. Now the motor runs really rough. As soon as I pulled my truck out of the shop I put the EGR tube on it, and drove it around and It ran great and quiet. But then later that night it started shaking real bad and service engine light started flashing! I took to Auto-zone and got my codes read: EGR system failure, O2 sensor failure, (i think that's because of my straight pipes), MAS (Mass Airflow Sensor) Failure, and Cylinder 3 misfire. My main concern is the cylinder misfire and the MAS failure. Can anyone help?