TRMach1

Yesterday my car had a compression test done by my friend. The way he did it he only pulled one plug at a time and had me step on the clutch and gas at the same time said it was a "shortcut" from having to shut of fuel and ignition, said that's how everyone did it at the ford dealer where he worked at. Does that really yield accurate results? Through that method 2 cylinders got 240lbs and the rest where right at 230 another one was at 233 and one was at 120 while the last one was at 207. Both the 207 and 120 were on the same side. The reason why I decided to do the check was because I took a trip to orlando (200 miles from my house) and on the way back I stepped on it and saw that at high rpms it would smoke bluish smoke. It has never done this before until now so idk if its the valves, rings or what since my car had been smoking at start ups but it did stop after I did some checking and found out that I had a catch can so after I drained that out it didn't smoke anymore. So I guess I have been racing my car since last year when i bought it on 7 1/2 cylinders, poor car.

Sonic Mustang

I can't tell you whether that "short cut" yields accurate results, but I can tell you I certainly wouldn't tear into my Mach 1's engine based on any test that could be called a "short cut."

No different than a surgery. Get a second opinion.

TRMach1

Definitely, I'm going to take it to someone else on friday.

4vmach1

The way we do it is by pulling the fuel pump fuse, crank for 4-5 seconds with foot on WOT. The cylinder that's low just requires a leak down test so we can determine if its rings or valves, etc etc.