My 99 4Runner has started with a miss or something 2 days ago . It occurs when driving down the road at a constan speed or when pressing the gas pretty hard . It acts like it is missing . At first I thought it was the gas , but I ran it down to a 1/4 tank and re-filled with new gas from another place and it still foes it . What could be causing ?

 

Now I have noticed a rotten egg smell , could it be the cat converter ? I have no check engine lights or anything on . It is running like crap . Kinda like when a coil starts going bad . or like a clogged exhaust , I need help asap as it is my daily driver of around 125 miles to work and back every day

 

the check engine light has not come on?

Many things spring to mind-could be an O2 sensor, yes it could be the cat.

What have you found out? I would not just go throwing parts at it. MIleage on the vehicle please? 5 speed or auto?

 

hook up a scanner and check the live data. Watch the o2 sensor readings. You may have a pending code or a history code. Are you sure your check engine light works?