Engine light...won't accelerate please help URGENT
 

Hi experts,

About couple weeks ago, I had an engine light came on and couple days later my car did not accelerate at usual manner - acceleration was so slow that I barely reached over 40 mph. I researched and learned that spark plugs could be issue if it has not been changed since the purchase. (My car is 2007 manual and has about 83K miles now.)
I changed spark plugs and the car was fine until today. I went out for lunch and samething happened. The car would not acclerate.
I went to the dealership earlier this week because the engine light came back on but was told it was a misfire and the mechanic turned it off.

Can anyone please shed some lights on how to fix this issue?
I hope to do things I can before going to dealers. I am afraid they might charge my arms and legs for repairnment.

Thank you,

Jiyoon

Your new plugs aren't sparking because the ignition coils are shot too. New plugs don't mean anything if you don't have a current going to them to spark in the first place. Coils, plugs, and wires need to be change every 30,000 miles.

But since you have neglected to change them, your catalytic converter has clogged with all the raw unburnt fuel that was getting dumped into the exhaust and effectively blowtorching the cat. Your cat is now so clogged as to kill nearly any ability to make power, and is causing misfires on it's own on top of the misfires from the failing ignition. If 40mph is your max speed, then you are already WELL past the point where a clogged cat can damage O2 sensors and your engine, and in the danger territory of where a an overheating clogged cat can start a vehicle fire.

DO NOT DRIVE YOUR CAR UNTIL YOU HAVE IT FIXED.

You are past the cat warranty (8yr 80,000 miles), so you are going to have to either buy a new one ($1,300+), buy a used one from on the forum ($200-$600 depending on milage), buy a midpipe without a cat ($100-$500, depending on quality and resulting noise annoyance), but a cat element to have welded in ($100-$500 depending on what you go with), or gut your current cat yourself with a metal rod (Free). What your emissions laws are will help dictate what your actual options are.


Once you have new ignition and the cat problem resolved, be on the look out for engine damage and O2 sensor damage. My engine and front O2 sensor were damaged by a clogged cat that was restricting me to about 60mph before I realized the problem.

There have been a few vehicle fires from cat clogs too, I'm not exaggerating the problem or the danger.