2002 Q45 EXHAUST manifold question

[jimmyrodq45]

A little history;
My 2002 Q45 has developed a check engine light over the past year and it was already diagnosed by a few shops as being related to the right side(passenger side) bank 2 catalytic converter. This is the exhaust manifold one.
One of the other symptom's I recently had are some occasional system of hesitations especially in bumpy roads and a loss performance and gas mileage.

I had delayed addressing this for several months, but its getting worse and smog is due in December.
I went to Infiniti parts USA website to check on prices and so far they are most competitive other than buying used. But what I see is there is a large price difference between a 2002 Q45 exhaust manifold/Catalytic converter $686 verses a 2003 Q45 exhaust manifold/Catalytic converter at $398.
When I contacted them they could not specify the difference nor the price difference. they suggested I order the one designed for my car

I know there are some differences between the 02 and 03 related to the rear end gear ratio, but is the catalytic converter different?

Any help would be appreciated

[EdBwoy]

Did the diagnoses point to a cracked manifold by any chance? Also, are you getting a check engine light with p0430 code or something similar?

Assuming that the integrated catalytic converter is certainly the culprit, then I'd buy the cheapest OEM offering. Not sure exactly what could have changed between the 2 years, but I know that there were very few differences between the f50 q45 exhaust manifolds and the y34 manifolds when I was looking for a replacement. My issue was a cracked driver side manifold (seemed common to the range of vehicles - they came out with a redesign which was about 800 dollars versus the 300 dollars that was being charged for the passenger side).

I ended up replacing my manifolds with those from a 2006 m45, but noticed that my original passenger one had been patched too. Although I made a few modifications to make my new manifolds fit, this is my way of justifying why I don't think those cheaper manifolds would cause any issues. YMMV

... or order both from the local Infiniti dealership if they'll let you, then just do a visual comparo.

[O5Q45]

I hadn't heard of any differences in the VK engine . I do remember before buying the 05 calling Infiniti dealer and asking what to look for in these cars and what they are known for and what had they seen. The 20+ year advisor said these cars catalytic converter goes out and if not fixed promptly ceramic dust gets into the motor and that's fatal. Am I way off here or could this be a possibility to your loss of power/fuel milage? Have you pulled a plug to see how things are going in the engine?

[jimmyrodq45]

Thanks for some of the feedback
Yes the error code was p0430 or p0420 either way it was diagnosed as bank 2 which is the right side.
The spark plugs were checked out and look ok given the mileage 182k and last replaced date they were replaced.
I was considering ordering the 2003 Q45 exhaust manifold with Cat, but ordering both 2002 and 2003 part is not possible given the 20% restocking fee plus shipping fee going both ways.

I will reluctantly order the 2002 Q45 and pay the extra $288
Labor to install this unit is approx. $400-$450. I know this is large expense for a 15year old car, but it looks pretty and drives sweet with the lowering springs/19" M45 wheels+body kit

[EdBwoy]

You're most welcome. I understand the cost restrictions. At the end of the day, it's hard to put a price on peace of mind... Plus it's easier to warrant the correct part with dealership workmanship.

I hope you get back on the road in tip top shape soon.

[Jason B]

So, I'm a magnaflow dealer and they now offer driver and passenger intake manifold, but it shows for 2003+ q45, and not 2002. Would it work?

http://www.magnaflow.com/products?partn ... levehicles

And here are factory ones:

http://www.infinitipartsusa.com/2002-In ... -59605.htm

vs

https://www.infinitipartsusa.com/2003-I ... -64234.htm