I've only had the doghouse over the engine off twice in the 12 years I've owned it. Once when I first got it to remove the 65mph governor, and recenlty when I was diagnosing the clogged cat, I replaced the cap, rotor, and spark plugs. Also replaced the fuel filter and then dedided everything else was good, no check engine light. Didn't feel much exhaust out the tailpipe, so I took a gamble assuming it had to be a clogged cat and drilled about 8 holes in the cat and drove it home from Abilene to OKC fully loaded with my daughter and son in laws stuff towing my 18ft trailer loaded, at 75-90mph. The truck is slow to get the speed up, but once it gets there, and whatever weight it'll run uphill at about any speed you want it to. I don't really know what it will run, I just know its fast enough, and even a bit stupid to be running with the 85mph speed mega pegged with that much weight. It was a military move so we had to weight before and after since that is how the military knows what to pay them for a DIY move. The truck, trailer and all the stuff on it weighed 14,100 lbs and still climbed small upgrades at speedo pegged. I was just in a hurry, cuz I was supposed to be there to Abiline and back to OKC in the same day. With the truck broke down, I worked on it for almost a whole day, got it fixed then had to load it up, so I was 2 days without sleep and scared of falling asleep driving. So kept the speed up to get home quicker and keep the adrenalin up to keep me awake. I had left Abilene, TX at about 2am, and was home in OKC by 6am, and hit the sack and crashed. Got up about 1pm and started unloading.