I replaced the one plug that i didnt get to replace the first time i did my plugs. but the vibration isnt as bad as it was. what else could it be?

 

motor? mileage? maybe a vacuum leak? is the cel on? any codes? could you fill us in with whatever you've done? vibrating at idle as in a misfire? low idle?

 

its a 1998 ford f150 4.6 with 146,000 miles. hypertech programmer, aem brute force intake and flowmaster super 44 sido. idles at 900 but just vibrates noticeably over stock. started noticing it a few nights ago when i started the truck. but the vibrating has calmed down since i replaced a old plug. but the cel is on. but its been on cause a damn egr. but it was blinking until i changed the plug.. but other than that i might need new wires.

 

If the CEL is on, read out the codes and FIX WHAT'S WRONG before trying to troubleshoot a rough idle by throwing parts at it. If you have an EGR problem, FIX IT.

 

that happened with my truck 2 weeks ago, you just need to clean the water from the plugs because they don't work ok when they are humid? humidity idk i'm mexican haha

 

, nice