Why is my '98 q45 losing power

[bena98q45]

Hello,

I have a 1998 Infiniti q45. Every time i drive it the car drives ok for a few minutes but then it starts getting sluggish. Any time i accelerate the car sputters like it is not getting enough fuel or air. I changed the fuel filter and it was better for about a week. now its back to the same problem. The car has never stalled or even died on me. I have noticed smoke coming from under the hood ocassionally and when i looked for the origin i could see it was coming from behind the block somewhere near the middle or drivers side of the car. I dont think its a fuel leak though because it has a different smell than burning gasoline. Also the car seems to do it worse on warm days or when i have driven it more than normal. could it be that my maf sensor or the egr need to be cleaned, or maybe a fuel injector,o2 sensor, or my knock sensor. the catalytic converter? what things can i do to diagnose if it one of the things listed.

Also Im pretty new to working on cars, but i just cant afford to pay someone else right now. Anyway......the more detailed and explanatory your response the easier it will be for me to understand what the steps are to diagnose and repair my baby

Thanks Ben

[NightRiderQ45]

Could be multiple things. Read my thread in my signature and report back.

[bena98q45]

Well i pulled the maf off and cleaned it. I also replaced the dirty air filter. This seemed to help. The car does not jerk or buck like it used to but it still is not fixed. The car just feels like im driving a 4 banger. When i press on the gas it just does not resopnd like it should. Im headed down to get new plugs for it today. Hopefully thatll help.

Could it be that the catalytic converters are clogged.

[Q45tech]

CATS usually melt from a extended use without proper A/F ratio. Various tests [backpressure] and thermal plus emission to diagnose.

[NightRiderQ45]

loss of get up power, especially when pulling hill means bad knock sensors. Both of mine are shot and I need to make time for fellow member on site to fix mine. As long as I'm still moving on the road, that isn't a huge priority right now since I'm busy with work.