hello guys, Just bought an 02 I 35, same as maxima a few days ago, A few issues with it i was told by the owner that it needed a cat, but i dont know which one needs replacing. Run and starts everytime, drives good, 180K. Was up north for half of its life, then in the south a few years so the exhaust has a hole in it somewhere. I do notice that regular driving is not a problem, but when you step into the throttle, there is a struggle for power like the engine cannot put out full power. Plan to replace the knock sensor and do a full tune up, iridium plugs, pcv valve, oil change, ect. Would like to get the full power back but dont know where to start in the exhaust system. Dont want to put too much money, and dont want a really loud car either. There are no check engine lights but its obvious that the engine is struggling. I dont know yet if its an oil burner but i do check the oil everyday as ive only driven it maybe 200 miles.

 

Several things, well first off, if the cat was bad, you would have an engine check light on for sure, which will through OBDII scan to see what problem codes you might have. The second thing, if you think it might be an oil burner, I would pull the plugs, those will be a telltale of clues if it's burning oil, such as burn oil or sludge on the plug. As far as power struggle. the Transmission problem could blogged down, unfortunately those do not through engine check light since they do not have to do with emission control or engine management. Good luck with the car

 

If the pre-cats were bad yes, main cat, no.

Yeah check for soot on the exhaust tip and also the air filter.

Exhaust repairs is usually easy if it's on the cat-back.

 

thanks for the replies guys, Yeah Im assuming the main cat maybe bad because the transmission shifts fine, will call around see how much that will cost to replace. Other than that so far, the car runs great aside from the hole in the exhaust i, i like how the engine sounds.