Bad idle and shaking while at a stop light or in park.

[Bobby Boy]

New member and need help, I have a 1999 Explorer XLT SOHC with idle problems. Have cleaned IAC valve, changed upper intake gaskets, new fuel pressure reg. Have cleaned everything that can be cleaned. Idle is fine when cold, heats up and drops to 500 to 400 rpm and the whole under carrage rattles and is very noisey. replaced plugs by ford dealer and it ran good for 6 months until it got cold and ruff idle started all over again. took it to new garage and they found that the spark was set at .045 and it calls for approx .054 after they changed the gap it took a week and it ran worse. only code that came up was to replace the fuel pressure reg. need help like my vehicle but bad gas mileage and ruff idle is driving me nuts. I hope someone out there could help. Thanks

 

[Sams01XplrSprt]

welcome bobby

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the stock 95-01 section. What was the code number that came up? How are the spark plug cables? Which brand did you use for spark plugs? Did you check the harmonic balancer?

 

[jlsparky7]

definitely have the codes pulled again. Sound like the plugs are fouling and it might be running rich? What do the old plugs look like? What kind of fuel are you running? Replaced the fuel filter?

 

[swetrid]

Did you replace the lower intake gaskets because they are the real problem with lean codes?