Just bought a 1996 Jetta GL with 126,000 mile s on it. No problem driving it an hour and 20 minutes from where I bought it to where I reside. Just put gas in it for the first time (87 octane) and 5 minutes later my speedo drops and engine dies.   Checked on oil level and it looked like it hadn't been changed in a bit, kinda sticky. Added about 6 quarts of oil. In the process of checking the oil I noticed that the dipstick had black electrical tape around it. I removed it wondering why it was there. I found out 20 minutes later when my car dies again that it was probably serving as a dipstick seal,
so that oil couldn't spurt through that part. Car is back home, and I have heard that all I need to do (from the guy at pepboys) is seal that dipstick opening until I can get the OEM part. Sealed it with a screw and some ducttapet, but now my car is pinging a lot. Came inside to look online as to what may be causing that. Went back outside to see if anything had changed. now it won't start at all, and I'm seeing rainbows from oil and water mixing. This makes me think there me be some leak I didn't notice before. Is it coincidental this is happening after I got gas? No problems for the last 4 days at all until today. Kinda frustrated cuz I just bought the damn thing and in the test drive it was fine.

Any help? Thanks a bunch.

M-Illinois