hey guys well i have been having some problems with my car for a week now and it is pretty weird so hopefully you somebody out there has had this same problem.

Well last monday i was driving home and i noticed my car wasn't driving right, i lost acceleration power and was slowing down. the car seemed like it was hesitating and all i heard a lot of popping sounds coming from my tail pipes (sounded like backfireing). I then noticed my rpm gauge was hovering between 0 and 1 for a while. well when i slowed down to about 15-20 mph, the problem went away and I had full power again. The rpm gauge was still not working right and when i stopped, it actually stopped working all together. so i drove the rest of the way home without an rpm gauge which is no big deal. I figured I would get someone to look at it in the morning.
When I started my car up the next morning, everything worked fine so i figured what ever the problem was, just went away. well on friday, i went to the bank and when i was sitting there i noticed quiet puffs coming from my tailpipes. when i went to leave, all my car was doing was making backfire noises and i had virtually no power.
I was able to get to a parking spot and got a ride home. my dad and i went back 3 hours later and she started up just fine but about half way home (which is less then a half a mile) i again lost all power and was able to coast into a parking lot. when i got there, my car died on me and it took a while before she started back up again. well i had to get her home and when i was waiting to leave, she died again. tried starting her up and again took a while. well when i was finally able to get her started back up, she was fine and i was able to drive her home without any driving problems. my RPM gauge stopped working again but she drove fine.
also my dad said that when i was having the problems, a lot of white smoke was coming out of my left tail pipe but nothing was coming out my right tailpipe. now the spark plugs and wires have less than 5k miles on them. somebody mentioned it could be my catalytic converter (i have two so maybe the right one is plugged), while someone else mentioned that it could me my cap and rotor. if you have any suggestions please reply because my friends and i are pretty confused by this. Thanks

 

Im thinking cat's.

 

I would check the coil, with your tach input going away I would start here. If it internally shorted itself out it would loose secondary voltage when ever it heated up. Then when they cool down they will work again until they get hot again. If you remove the coil from the head you should be able to see discoloration on the coil body. The other thing that comes to mind is the TPS might be throwing a code. My 97' WS6 had this problem when I changed to a Holley TB (I do not recommend the Holly TB) and it when into limp mode. It would run ok until 3K and then shut down and go to the next gear on my A4. Paid a $100 to have the TPS modified to get it back into the normal readings to work properly (closed 0.5 volts, wide open 5.0 volts).

 

thanks for the input. I am going to start with the coil and if that looks fine then i will check the cat.

 

With my beater it was the cat. It go to the point that it would die on the highway. Then would not go faster then 45mph(with the gas pedal on the floor), then would not drive at all. When it first started I would slow down and it would go away, then it just kept getting worse untill I had to get it towed home. Was doing the same thing your car is doing and mime poped some.

Replaced the cat and it went away.

There is a video on a CTS-V in the video section and his car was doing the same thing and you see it in the video.

Also may want to hook up a fuel pressure gauge and test that first also.

ALMOST sounds like a fuel pump wanting to go out but I am going to say cats.

When my pump went out it would pop hard out the exhast, I would have to floor it and then all the sudden power would come on, RPM's would sky rocket and it would blow the rear tires off. Was hard to restart, then the next day it would not start.