QuestionI HT,
I have asked some questions a couple of months ago. I have a Hyundai Santa Fe 2.4L automatic with 121k miles which had one of the cylinders with a low compression (~90 psi compared to the other 3 cylinders with ~150 psi). I went to the mechanic and told me that the valves of such cylinder were burn out, so I decided to let him do the work. In addition, the exhaust manifold was replaced because a strong gas smell inside the cabin.
After that I didn't notice any improve in the performance (i.e. more power, fuel saving, etc) other than the gas smell is gone. However, now the car is very noisy everytime I push the gas pedal. The noise is coming from the pipes after the joint with the exhaust manifold. The mechanic told me it was due to the extra power the car has after the valves job.
Just recently, I was driving on the highway and the car started stalling and didn't build up speed (no more than 60 mph,and no more than 40 mph on slight slopes).In addition I noticed a very bad gas milage efficiency. I went back to the mechanic thinking that the problem could be due to work done (i.e. head gasket or valves no working right). So, he told me that it could be due to the catalytic converter. He cut the pipe and told me that the catalytic converter was pluged up.
Changing the catalytic converter will solve the problem? Will it have any effect on passing future gas emission tests?
Could you plese help me with the car diagnostic?
Thanks in advance,
AnswerEverything you've told me is consistent with a catalytic converter issue, even the noise from the exhaust that the mechanic said was due to the extra power.
If disconnecting the exhaust in front of the converter allows the vehicle to run properly, then it's a reasonable conclusion that the converter is clogged.
