1988 Ford F-250 460

I'm chasing a slew of issues in my f250 that I need some opinions on. I've fixed tons already but theres a few pesky problems that remain. Hopefully this isn't too much for one thread.

To start things off, I replaced the short block a few years back due to a cracked block and theres been several problems that I haven't solved yet. For one, the EGR apparently quit working according to the trucks memory codes. Tested it with a smoke test and it was leaking so it has a brand new EGR. Still have the code. Maybe I didn't clear it right, or possibly a bad position sensor. Any thoughts?

Second of all, the truck has had a lean code since the engine replacement. I can probably tell you why. I replaced the exhaust system and added long tube headers and true dual exhaust. I placed a new o2 sensor in the passenger side collector, because I wasn't sure if it needed to read both sides of the engine or not. It doesn't seem like its farther away from the engine than the factory location but maybe. The truck also has a brand new in line fuel pump, and the in tank seems to be pretty strong. I have a fuel pressure tester but haven't had the time to check it yet. Any thoughts on this?

Heres my most recent and concerning finding with the engine. I've had brake issues but seem to have resolved most of them, but my power brakes seemed to be just a hair hard. It comes and goes so I suspected a vacuum leak. This truck has had tons of vacuum leaks and I think they're all fixed, but it is still a possibility. Anyway, I tested the vacuum and it was decent, about 18-20 inches at idle. Heres the kicker. The vacuum gauge was very erratic in a random manner. I looked up the cause and they are pointing to worn valve guides or sticking valves. The truck did seem to burn a small amount of oil from time to time but I was not suspecting worn piston rings already. Also, there is an audible hissing sound after shutting the engine down, then my vacuum disappears. I should have had the heads rebuilt, but when I rebuilt the engine I was only a poor high school kid lol. Looking back I should have spent the money. Could my valves be leaking and causing these vacuum issues, or is there no correlation.

I can add pictures if that helps. I also may be forgetting something so just ask if something is unclear. Like I said, hopefully this isn't too much for one thread, but I really could use the advice.

Any assistance is appreciated!

 

Yep could be the sensor or a leak in the vacuum line between it and the EVR or the EVR itself.

It doesn't and this isn't a problem.

Yep you still have a vacuum leak. Did you smoke test the vacuum system? If not give that a go, good possibility you will find a leaking vacuum canister or something inside the dash.

Do a compression and leakdown test, that will expose any internal engine problems.

 

So I probably need to look harder for my lean code issue. I did do a smoke test however I didn’t think to check under the dash so that is a very good point. Maybe the leak down test will reveal any further issues within the head.

Thanks!