03 Z touring 87k. about 2 months ago it started breaking up and spitting whenever i got on the throttle (to pass of course). first thing i did was change the spark plugs. they looked pretty burnt up so i figured that was the issue was. it ran perfectly for about 2 weeks and then started to doing the same thing. it has gradually gotten worse. it runs fine when your just cruising but if you get on it at all, it loses all power. im also getting a bad rotten egg smell ONLY under acceleration. i know thats a sure sign of a bad cat but could that cause the breaking up issie too? Also no check engine light. ive heard of having codes thrown without getting a light so but i havent gotten a chance to have it checked yet. what do you guys think?

 

Telltale sign of cat converter failing

 

Maybe if the catalytic converter is plugged, possibly from itself, it would have enough flow to keep up at low RPM low throttle but choke at higher throttle. Check your codes and long term fuel trims might be able to see what cat has the problem.

 

ran a scan on it and there are 0 codes being thrown

 

Delete your cats then report back.

 

Simple test: Lift the car and use an IR thermometer to take a temperature reading before and after the cats. If the downstream pipe reads the same as or cooler than the upstream one, then your cat is clogged and needs to be replaced.

 

Rotten egg smell is completely shot/clogged cats. It's that rare smell you will only smell a few times in your life time and 99.9 % almost always is the cats. Time for a cat delete or one of the $1,000 catted pipes

 

well it turned out it was just a coil pack. face palm