Quote Originally Posted by camoit View Post
Jet valves cause backfire and loss of power. If you stick a vacuum gauge on it you will know instantly.
I believe it..!

We replaced the head w/o jet valves nearing two years ago now & three months ago a new OTC vacuum gauge held a rock steady 28 or 29 inches of vacuum...

NEXT WORK ON TRUCK WILL BE:
1) Replace mechanical fuel pump with oem made in Japan pump
2) Remove clean inspect test the. EVAP check vavle back near the fuel tank
3) Begin using clean fresh non ethanol gasoline 5 gallons (only) at each fill