On June 11, 1995, about 1004 eastern daylight time, a Bellanca 8KCAB, N7631S, registered to APT Aviation, Inc., was substantially damaged during a forced landing on a road east of the Kendall-Tamiami Executive Airport, Miami, Florida, while on a 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The commercial-rated pilot, the sole occupant, was not injured. A vehicle struck by the airplane received minor damage and the driver of the vehicle sustained serious injuries indirectly related to the collision. The flight originated about 0940 from the Opa-Locka Airport, Opa-Locka, Florida. The pilot stated that at various times during the flight as well as just before the engine failure, he exercised the alternate air (heated, unfiltered air) control to verify operation. The only discrepancy noted was that the handle would return to the alternate position if not held to the normal (filtered) position. During cruise flight at 1,000 feet inbound to the Tamiami Airport, the engine failed. Emergency procedures included verification that the fuel selector was in the "on" position, the auxiliary fuel pump was turned "on" and the mixture control was pushed to the "full rich" position. The engine failed to respond and the pilot executed a forced landing to the north on the southbound lanes of U.S. 1. During the landing roll the roof of a vehicle was scraped by the right wing of the airplane which then collided with a tree. The airplane yawed clockwise and came to rest upright with the left main landing gear attached only by the brake line. Examination of the cockpit at the accident site revealed that the alternate air control was nearly fully engaged. The airplane was then recovered and further examination of the air induction system revealed a piece of paper in the air inlet of the servo fuel injector. The paper was about 28 inches long and had numerous areas of blue/green stains. The engine with propeller installed were removed from the airframe and placed on a test stand. The paper was removed and the engine was started and operated to near full rated rpm. The only discrepancy noted was an excessive magneto drop when operating on the right magneto. The sleeve (insulator) at the spark plug end of the No. 1 cylinder bottom ignition lead was found to be broken. Review of the overhaul manual for the engine revealed that the No. 1 bottom ignition lead is routed to the right magneto. Review of the engine logbook revealed that the servo fuel injector had been removed on May 8, 1995, and reinstalled on May 28, 1995. The airplane had been operated for about 3.8 hours since the servo fuel injector was reinstalled.