Owners/service Manual problems of the 2005 Ford F-150

When taking my vehicle out for test drive after putting new brakes on. While driving an spark plug blew out. While checking online I found that this is a major problem. I was very upset to find out from the dealer that it's gonna cost $585. 70 to fix one spark plug and replace coil. I asked about replacing all the plug and they quoted $900 to do all of them. As a retiree of Ford I think this is crazy. They tell you in the manual that the plugs are good for 100,000 miles. The mechanic said there is no guarantee that this won't happen again even if we replaced all the plugs. I'm thinking of trading my truck off and am considering another brand.

I had a sudden failure of the power brakes on my '05 Ford F-150 due to a vacuum valve that is located on the back side of the motor midway down of the motor on the back side between motor and firewall. This was not a warranty item due to my truck having 50,000 miles on it. The remedy is to get the 30$ valve and remove the top half of the motor just to get to the vacuum valve, due to the labor intensiveness of the job labor is $400. Luckily I did not have an accident but you will only have manual brakes when this vacuum line comes off in addition to a rough running truck.