New Catalytic Converter, then car begins to shake?

**Pyromaniacal** · 08-26-2006, 04:43 PM

I got my new Magnaflow Hi-Flo cat and my car runs much better then it used to, but now the car shakes like it has a 454 in it. The engine at lower RPM shakes more than I believe it should be, but the whole car still sounds monstrous. Also there is still decreased power, just not nearly as severe.

What could be wrong? My current hunch is one of the pistons isn't firing, possibly due to bad plugs/wires? What other possibilities am I looking at?

**SloLt1Camaro** · 08-26-2006, 10:47 PM

Check the muffler bearings!... joking. I'd check all the parts of the ignition, from plugs to the distributor piece by piece... Is the SES light coming on?.. Try checking to see if any codes have been triggered. I'm not sure if you have the OBDII computer or not, but if so, try checking all of the o2 sensors.

**Pyromaniacal** · 08-27-2006, 09:13 AM

I see, what kind of equipment does it take to read an SES code? Also the car is idling rough, let me see if I can put this into words for you, every time I hear the exhaust breathe, at the end of the breatheing the engine seems to take a dip, the supercharger makes a noise as if it was not being turned for a second, and then goes back into it, cycle repeating forever. Perhaps thats an indication of something gone wrong in the ignition, as you said?

I will check the ignition, plugs to distributer, but there is one thing I would really like to know, is the car safe to drive right now? Aside from the shaking and rough idle, it goes in the forward line correctly, doesn't generally have any problems, and sounds absolutely monstrous from the rear. I'd like anybody's opinion on this one, because I'm really having a hard time not driving it, even in its broken condition. Thanks, in advance.

**Pyromaniacal** · 08-27-2006, 08:17 PM

Going to repost this topic in "General Help" for perhaps a better response.

**SloLt1Camaro** · 08-28-2006, 03:39 AM

Your local auto supply store should have a scanner for it (AutoZone, Advance Auto ect ect.)... As far as safety goes, I wouldn't recommend driving it too much until you know exactly what's wrong with it... Usually if something's wrong, and you keep going, it gets worse.