Embarrased to ask, but need help
 

Well I'm just looking for a little diagnose for the car. I've had a series of problems as of late and I thought I had them all solved but I'm still having some acceleration hesitation. I had the transmission replaced about 5,000 miles ago and about two weeks ago I had the coils go bad on my trip to California. I replaced all 6 spark plugs and coils and I no longer have a CEL. I thought everything was swell until I tried to accelerate briskly. The car starts off like I remember, but around 3500 rpm at 3/4 throttle it feels as if the power is cut in half like the transmission is slipping or the ECU is just cutting power. It still accelerates but not very stong at all. Now I hate to ask this, but is this the transmission, the ECU needing to be reset overnight again or the dreaded MAF. I have no error codes so I can't be much more help unless someone has any tests to try. Thanks a lot.

Where was the transmission replaced and with what?

If you've just replaced the coils and plugs (assuming you used NGKs for the plugs), it sounds like it could be a bad MAF...

have you checked the VIAS?

Sounds like an MAF to me. Does the car run worse when the car's cold, when it's hot out, or with the A/C on?

The transmission was replaced with a refurb by Nissan as a warranty replacement.

I almost forgot, when the car is first turned on in the morning the idle is about 1200, where it is supposed to be, place it in reverse and back down the driveway without a problem. I then place it in first and the car totatlly bucks and almost stalls for about two houses worth then it seems to settle down. That's the only time during the day it does that, not at lunch or on the way home from work.

The coils and plugs were purchased from Dave B. Grey dot coils and standard NGK plugs. After reading this forum for years I'd think it was a MAF because I have read way more about that the VIAS but after reading this thread I'm thinking it could be the VIAS. A few other things I've noticed recently. Say I'm traveling at around 30mph and I floor the car (automatic once again) it doesn't downshift, it just is WOP throttle until third gear shifts to fourth after around 65-70mph. I really appreciate the help.

Definately sounds like an MAF. I doubt its your VIAS. The VIAS soes not even kick in till above 5000rpm. MAF's tend to have that same buck right around 3200-3500rpm's and will def buck when cold.

Easy way to check,

Find the vias (plenty of pics on the org) and reach under it until u feel a little bass looking bar. Once u find it, push it towards the car, if u get resistance, it likely fine, if it moves easily, it's toast.

it's your MAF.

Yep, plenty of resistence, I'll be calling Dave B on monday. Thanks for the quick tip.

sounds like the same symptoms i had when my MAF was bad...but dont ever be afraid or embarrased to ask...thats what we are here for

embarrased to ask because it's been beaten to death before, I just like to be sure before I spend more money on this old rust bucket.

Hay can u redline still????

In neutral yes, in gear the car shifts at around 5500.

I'm pretty sure Champ 2433 (and many others) is right on the mark!

My problem is when i floor it my freakin car after 100 mph wont goo and in second gear from 2500-3500 will drive ****ty too sorry for asking on your post

MAF or VIAS. Just get a MAF for 88 bucks from Dave B. I am on my 3rd. Changed it for the 3rd time last month. I am getting 360miles to the tank, and yes it is auto. When was the last time you changed the fuel filter?

not too long ago maybe 3 months

I replaced my MAF.
 

Sounds like a MAF to me. I just replaced mine and it fixed a high idle start-up (mine was over 1100rpms like you are experiencing). I also had the engine pull-back/hold-back power when around 4000 rpms. I had no check engine light for a few months. Then the problem gradually got worse (car would stall after start-up until I had the engine warmed-up) and eventually I got a PO171 engine bank rich error/check engine light. I used my multi-meter and found my MAF to be giving off bad voltages. I would replace the MAf if I were you as it can be starting to go bad without tripping a check engine light and may not give you check engine light/error code until the improper voltages read by the ECU perceives a problem. When my MAF was oging bad it threw off a bad o2 sensor problem, but my o2 sensors are fine but the bad MAF made my ECU think the o2 sensor was faulty. I am starting to realize that maxima MAFs are a root of a lot of evils.... After I replaced the MAF my car was fine and no more error codes or running probs.