1997 F250 HD 7.5 LITER WITH CHECK ENGINE LITE ON.
SCAN TOOL READ THESE CODES, PO401,PO171,PO174,PO305,PO232,PO300(SHOWED UP YESTERDAY),P1000. THESE SHOW UP ALMOST EVERYTIME.
P1506,P1127,P1703,P1780, THESE ONLY ONCE ABOUT TWO MONTHS AGO.
I'VE BEEN WORKING ON THIS FOR A LONG TIME TO CORRECT THE MOTOR PERFORMANCE AND STILL GET GOOD MPG.(8-10)
NOW I NEED TO SMOG THIS MONTH AND I COULD USE SOME HELP IN ANY IDEAS WHAT IS WRONG. ALREADY BEEN TO TWO MECHANICS AND PREFER TO DO IT MYSELF ANYHOW, I KNOW MY TRUCK BETTER THAN THEM.
SOME VACUUM LINES BROKE WHEN THE HEADS WHERE DONE AND I THINK THAT IS MOST OF MY PROBLEM, INCORRECT ROUTING?
PLEASE HELP IF YOU CAN, THANKS.

 

There should be a vacuum line routing diagram under your hood. I'd be certain that all of the lines are properly routed and not leaking before trying to diagnose the codes.

 

I have a mechanic friend helping me and checked the vac lines to diagram, they are correct. We took off the IDLE AIR CONTROL VALVE to check it out since it seems like the choke no longer works, do you know how to test one of these?
Also found that #3 cylinder is weak and #4 not working. Doing compression check next.
Spark is good, Fuel injectors?
Any ideas? Thanks