Coming home from work today my 1997 GMC Yukon 1500 with the 5.7 liter v8 started to rumble like crazy as I accelerated. The check engine light was flashing. Whenever I hit the gas the car shook like an earthquake. It also Idles like shit but when in idle the check engine line is in solid-state with normal amounts of rumble. The rumbling is the best when traveling at 30 mph where it feels almost normal. 5 years ago this car had a cylinder misfiring and the experience was similar, back then I was told to drive fast and it would fix itself. The other thing is I put regular 89 gas from shell in the vehicle which is normal as I usually cycle 89 and 93 to limit carbon buildup or whatever so I don't think it is gas related. 

My 1987 Ford Thunderbird Turbo Coupe with the 2.3 liter four-cylinder has a boost leak that is horrific or more likely the turbo is just broken. It doesn't like to go over 50 mph and the check engine light turns on while the car is over 2800 rpm. The car also doesn't rev above 3000 rpm and will actually accurate slower the harder you press the gas making the optimal position to go a light press.

I need to go to work tomorrow because I need my time and a half or I can't pay my bills and fix the cars. I have to choose one. Which one do you think is safer to drive 15 miles to work. I need to pay my bills while minimizing the cost of the repairs to the Yukon. Thanks