Hey all, I very recently purchased an 03 Maxima 6MT. Got it at a decent price. Has about 170k. Right from the start I noticed that the acceleration was not up to par and a couple days after driving the SES light came on so I purchased a scanner. Got a P0300. After looking in the forums I tried all the common fixes, Cleaned the MAF, etc etc. Then after seafoaming last week I finally got a different code P0306. So I changed all the sparkplugs, plenum gasket, and even got a new coil pack for cylinder 6. Engine still preforming the same, still doesnt sound right, still have a major lack of acceleration. From 3k rpm to redline it is SLOW. Also have a flex pipe leak but bought a warpspeed y-pipe im putting in tomorrow, any ideas?

Also I came from an 02 Civic that pulled harder than this :/

 

Clogged precats are a common problems on these cars, and they would certainly limit your acceleration. You'll know for sure after you remove them and install your y-pipe.

 

I don't think the pre cats are in the Y pipe,
I thought it was Headers/precats -> Y-pipe -> cat

 

Yes. I assumed you would be removing them. There are quite a few posts on the subject: just search for "gutting pre-cats".

 

My oil consumption is high, some people have told me that this means that it might be too late/not worth gutting the pre-cats. I don't want this to turn into a money pit

 

You do realize that by not gutting them/installing headers, you will just kill the engine, right? Oil consumption will continue to increase to the point where you'll have to swap motors or junk the car.
Either gut them and feed it oil or swap the motor. Every time you drive it, you're just ruining it more.

They sold it b/c they knew it was shot.


5.7 swap /thread

 

So you're saying that if I don't gut them, always check oil/keep it filled,
its actually killing it just from driving around?

 

whether you gut them or not you will have to feed it oil. The damage is already done and by not gutting the precats asap you are simply making the damage worse. At the end of the day if you plan the keep this car for a long time I would start saving for a swap down the road.

 

The leak will make it slow for sure.....I once had one that developed after stomping on it hard lol......power was gone real quick.....maybe its just that. Good luck.

 

I'd bet on the precats, had the same issue with my 4AT Maxima, seemed to get slower gradually over time. Replacing the precats and also doing the NWP block off plate knocked 3 seconds off my 45-85 time. Precats were in terrible shape, replaced them with lower mileage ones I got used from a member here for $85 for the pair.