92 4.9 idles to high
#21
Bad vacuum from the MAP sensor to intake is a definite possibility. Another is your Thermactor vacuum system if the idle only raises intermittently when the solenoids open each line.
#22
Senior Member
Do u even know what engine vac is? Tb plates should be completely closed. Take the cables off and open it and let it snap back. Tb get hot and warps over time. U have a miss, what color are all the plugs? When u measure vac what is the needle doing? What is the fuel pressure? Do the injectors look like they have leaked? Sea foam in the gas tank helps with any water in the tank and it cleans the injectors. There other things to check and test but finish the basics first.