Need Advice On 1995 Cav!!!

The car was driving bad and stalling the Speedometer and Temp Gages were shooting around and behaving erratically and I had a Check Engine Light.. i did some research and ended up replacing the Oxygen Sensor and the Spark Plugs... It started up fine and i drove it around for about 15min and it seemed fixed.. It drove smooth, no engine light, and no stalling, and the gages were fine.. But suddenly I got the engine light back and the gages started shooting around but the car still drove smooth. so i drove back home and parked it.. Now it wont start.... I checked the spark plugs and the battery and the oxygen sensor and every thing was fine... i messed around with it some more and got it to start by tapping on the Guages... Kinda weird... My guess is that its sensing a problem with the gages and the computer is telling the car not too start but I'm not sure??? Whats your advice..? I also noticed the harder and faster you tap the Speedometer the more the engine starts and the better it runs but if you stop tapping it the engine shuts off...........WTF?

lol wtf? x2 - wiring/electrical problem? possibly with the security system? :screwy: