Hi
121k 2002 6spd...Had it for 4 months now and headache.....Our other 2003 GLE auto with more milage is MUCH more powerful than this 02...My 97 gxe auto was even better pulling.....
1.Changed Gear oil to Amsoil 75w90
2.Changed lower oil pan
3.Changed oil(Castrol GTX 10w30) 3 times in 4k miles with 3 Nissan filters
4.Changed all spark plugs with NGK laser platinum and manifold gasket...didn't find leaks of oil , just 1st ignition coil was dirty (becuase I washed my engine when I bought the car ?) .. cleaned
5.Radiator new coolant
6.New precats , new Y-pipe and main cat
7.New 2 front oxygen sensors , cleaned the downstream two
8.New MAF (2k1 ---> 2k2) mod with an aftermarket thermistor
9.Shell 93 octane allll the way , I never put less than 93 octane on all our cars
10.Now on 2nd Seafoam can in the gas tank( I do not see some real effect)
11.TB cleaned when inspected by the dealer (my worry is that they messed it when that was done)
12.New Nissan air filter
13.I guess my ocasional transmition grinding in 3rd is pretty common here
14.Clutch is in fair condition,although it acts lil funny when I drive for 1 or 2 hours in rush stop and go traffic when I press it real hard (master cylinder?)
15.Tires are Firestone Hawks GT crap,fair condition too(maybe more than half the tread left)....I don't see myself throwing more money toward 4 new tires now
16.Clunky front suspension...(same comment here like the point above)
17.No SES or codes

Even myself when I see this list , I would think "oh man , I have a real rocket car now) and the fact it isn't..... Although I do no step hard on any of my cars (always in the 3k RPM) but I wouldn't do that either to my wife 2003 auto or my old 97 , and they always pull and accelerate better (unless I go around 3-4k rpm in this 02 in which I don't like)......I feel ebararessed when I am passed by a camry or corolla from a dead stop( the car is little better when cruising in the 40-50MPH range if I would pass someone)....
What do you guys think ? thanks...

 

Just picked up a 6 speed '02 to replace my totaled 4AT '02 and the new one is definitely quicker.

If the cats were bad, could be debris in the muffler from them coming apart.

 

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Congrats on the new 6 speed .....
the old main cat had intact mesh that most likely prevented any debries from going further to the muffler(I wouldn't also think some debries would kill half the power)...And for sure , the old Y-pipe had debries to hell

 

intake filter, cat converters, non functioning vias.

 

I have 4k now on stock Nissan filter(stock airbox)
2 New Magnaflow pre cats
Not sure about the VIAS ... And No SES light

 

Did u get rogeezy's..... man I love that color if u did

 

I haven't had a functioning vias for nearly 2 years ... And No SES light as a result. It would have horrible top end power if it wasn't opening.

Where is the power loss, mainly? High RPM feels weak? Low rpm? All over?

Does it feel like it's running rough, stumbling, or does the engine sound like it's lugging?

Does it burn oil?

Compression check?

Seafoam the intake manifold through the brake booster?

Have you quantified this lack of power in any way other than butt dyno? It will always feel like you're driving harder in a 6speed to accelerate the same as a 4AT, both because of the torque multiplication from the torque converter from a dead stop and from having to shift much more often with lower gearing.

 

He wasn't able to get home to see if he could get the seat working and I really needed to get a car and stop paying for a rental. Found a 6 speed car locally, his was a 4AT. I do really like the color of his though.

 

Clogged main cat will definitely kill power (and it completely clogs when the precats fall apart, ask me how I know). And sounds like an ignition timing check is in order if a test pipe doesn't fix it.

The engine does have another 3.5k to go for future reference LOL. I didn't know under 4k even existed.

 

1.VIAS -------> I think it would kick in after 4.5 or 5k RPMs,I don't go there much
2.For the RPMs ------> all over
3.For the engine behaviour ------> engine revs fine , though I have slight (very minor) idle hesitation at times , idle around 550-600
4.Oil burning ----> yes , around 1/2 quart / 1000 miles or so
5.Compression ------> not checked , probably I would let someone like the dealer to check my timing
6.Seafoam the manifold -------> no,I am affraid to bring more problems to myself,but that's just me
7.Dynoed -------> no,only my butt did
8.Driving style -------> more and more each day I would agree with this , much different the 6-speed than the AT....I used to drive my old manual trans car back in my country of origin for 10 years , but again that was different from my 02 maxima , it was RWD 2.8L V6 toyota supersaloon

 

thanks for the reply........

YES...For sure clogged cats kill power , currently I have 2 NEW magnaflow precats and a new high flow main cat......along with 2 new Denso upstrean oxygen sensors....

 

Oh. O.k... congrats non the less.. start a thread n post pics

 

The op went to town on possible issues, so I can't imagine he didn't look at the intake filter.

But the VIAS... that's a good one. If the there were a vacuum leak in the VIAS system, that would throw a code. If the VIAS solenoid were malfunctioning, that would throw a code. But if the valve itself were sticking, I'm pretty sure that goes unreported. OP, it's an easy thing to remove the VIAS valve and inspect it.

Good luck, man. It sucks to be so disappointed in your car.

 

1. If the VIAS was stuck open for some reason (or the previous owner gutted it to gain top end), it would affect power from idle to 3800 RPMs to the tune of over 20wtq. Not too likely, though... I would still take it apart to check. It's only 3 bolts that are easy to get to, no serious work.
5. It may be worth checking. If it's losing oil, always possible you have some bad piston rings and making less power than you should due to lower compression.
6. Seafoam won't help much on a car that is driven hard often because the carbon deposits tend to get burned out... but on a daily driver like yours that rarely goes over 4k rpms, it can be very beneficial. If you do it properly, you won't hurt the car at all. There is probably a how-to thread somewhere on these forums.
8. Yeah... when putting around town and going from an auto to a 6 speed, it usually does feel slower at low rpms. Strange but true.

Also, have you taken apart the intake to make sure there's no obstruction on the MAF screen?

Way to test if your TB is opening all the way like it should: Turn the ignition to on (don't start car), put it in gear, then prop something to hold the gas pedal to the floor. Pull off the intake at the TB and look at the plate. If it's not open all the way, that could be your culprit. When it's in this position, it can be cleaned if you wanted to. It sounds like your idle is low for sure and that may help.

You never know on simple stuff like that. It's easy to look over something when you're frustrated.

Believe me or not, but as long as the vias solenoid is left plugged in, you can remove the plate all together, plug or remove the vacuum lines, etc... without ever seeing a code. You might wonder how I know that and I would tell you that my vias solenoid is hidden next to my LIM in one of the dips between the fuel injectors, still plugged in to the ECU connector but otherwise all by itself (no vacuum lines) so it doesn't throw a code.

 

Have you had the ECU reflashed?

 

To piggyback on sparks's comments. Check the plastic clip on the rod at the VIAS. Mine was broken when I purchased my vehicle. Quick fix.

Also, a loose front end will not allow the power to get to the ground. I cannot believe how hard my car launches now with new front end components and an alignment. Most of my power was being lost to excessive wheel movement.

 

id say have them do a compression test, other than that theyve covered pretty much everything else.

 

OK.......If I take the VIAS out , should it be cleaned ? inspected ? what ? carb cleaner ?

is there a write-up or something here ?

 

Just push on the rod, you should feel it moving.

 

I just ran over this thread as to why my car was bogging. When I step on the gas it hesitates then pulls. Also when I rev my car the tach shudders coming down, it doesnt come down as smoothly as the other cars i've seen and I have a low idle. Any thoughts?

 

I have similar issues. Mine acts like there's an exhaust obstruction; or like the fuel injection is clogged. It takes off, then hesitates, then takes off again. Something is clogging something. I put on a new catback (muffler was toast) and was going to put a new main cat, but the guy who did the work looked at it and said it was in great shape and there was no need to change it. I had to gut my precats a few months back and the insides were a mess, so I was surprised to hear the main cat was fine.

I replaced the MAF with the 2001 adding the thermistor; put top quality iridium plugs in about 30k miles ago; always had good quality oil, but burns at a similar rate to OP. I seafoam gas tank and intake a couple of times a year; new fuel filter, nothing but 93 or above gas. I have no codes. I'm also frustrated and can't figure out what the problem is unless the mechanic was wrong on the main cat (I should have looked myself). It has been progressing this way for a while now, but used to have solid power. I'm about ready to trade it in.

 

In another thread. IIRC, the guy said his VTCs were stuck from deposits and was very similar to this b/c he already replaced everything, but it was still slow.

Has this car always had dino oil in it?