'06Roush_150

I may be wrong but wouldn't a vacuum leak suck not blow... I've heard of people using propane and if the idle increases you found your leak.

vintageman

I have been using soap and water in a spray bottle for years and it definitely works. You can also use something like throttle body cleaner and spray that and if the idle revs up, you have found a leak. Let us know how it goes.
Tom

xrider

I must confess I too am in a state of wonder concerning how spraying a soapy solution is going to reveal a vacuum leak. Explain away please.

'06Roush_150

Anyone else use the soapy water method? I can't wrap my head around it.

BUCKSHOT

That is the correct number SP515, I just went through this myself with a couple different Ford mechanics. Both said that your playing with fire if you try to use anything other than Motorcraft in these engines. They have seen more engines not run right or the plugs foul out way early than they have seen that run fine with brands other than Motorcraft. Just my .02 worth with what I found out.

xrider

I agree with BUCKSHOT. Put the 515's in, put the nickel anti-sieze on the bottom half, run a can of Seafoam in the tank prior to changing them, and change them after 60k, and I believe the odds are good that they will be ok.