Stange Problem and Solution

[DANNOV]

For some time my 1985 Carrera has had a misfire problem at about 3000 rpm. When cruising at 3000 rpm in 5th gear for about an hour, I would suddenly get a rather violent misfire. Very similar to a vapor lock type of misfire. In my old TR4 whenever that happened I just dropped down one gear and got higher RPM's - more cooling - and the problem went away. This technique also worked with my 911. If I went from 5th to 4th the problem would disappear. I thought it was a vapor lock problem but several Pelican people said that vapor lock is not a problem with modern fuel injected engines. A lot of people recommended that I replace my ignition wires. I did that but it made no difference. Earlier this month I had the car out on a PCA DE event at Blackhawk Farms Raceway. I went into the carousel at about 3000 rpm in 3rd gear and as I attempted to accelerate my car suddenly started to misfire. This was a bad situation because a sudden loss of power while in a long carousel can provoke oversteer. It was a bit scary for a moment but I was able to control the situation. I thought it was one time problem but it happened in the 2nd and 3rd sessions at about the same place and speed. Driving home that night I got the same problem again, a loss of power when cruising at exactly 3000 rpm, which I could correct by going to 4th gear and a higher RPM. I was somewaht concerned because I was planning to go to Road America over Memorial Day with the PCA, and Road America has a really long carousel. Losing power in the center of the RA carousel could cause a real problem. I reluctantly took the car to our local Porsche dealership - I hate going there because they are so expensive. - but everyone else was busy. The problem was a defective speed sensor. In addition, I had the head temp sensor replaced. This worked, the car had no reoccurence of the misfire. The cost was $1,400 of which $600 was diagnostic time.

That is the good news, the bad news is that when I got to Road America I put both left side wheels off the track into the mud going into Canada Corner (#12) and was a 100 MPH bulldozer for about 100 yards. I clipped the edge of the retaining wall - 3 feet more and I would have been safe - and damaged the front and rear quarter panels. Not severe damage, only about $3,000 worth. It could have been worse but this is the only serious mistake I have made at a DE event in about 5 years. There is a lesson to be learned here and I don't mind paying the price to learn a valuable driving lesson. The lesson is that when the track is damp - even slightly - leave some margin for error in the braking zone. Don't start braking too close to the edge of the track, especially when the wall is close. I hit a damp spot under heavy braking, fish tailed and the rear end slid over the edge of the track, after that I was caught and the only thing I could do was to try to keep straight and away from the wall, and I almost made it. The problem started at 110 MPH and I hit at about 10 MPH. Pictures will be posted shortly of the crash damage. I must say that it all happened in slow motion and my most vivid memory was of the corner worker who stood his ground as my out-of-control car approached and then dodged out of the way at the last last second, like a bullfighter.
Dan Novak

[Superman]

It makes a good story. And I would agree that your local dealership's pricing is breathtaking.