Loss in acceleration + throttle response ??
 

My car has roughly 3850 miles on it now. I did the oil change this past weekend. I used Red Line + K&N combo.

Ever since the weekend, I have noticed that my car seems a bit sluggish (bogged down), especially at lower RPMs. Now, I know the car is running quieter with the new oil, so subconsciously I could be making a connection/relation of sound to power/speed but I doubt that's it. I think it's just a coincidence that this is happening after the oil change.

There are times with I get on the gas and get little response and then all of a sudden the torque decides to kick in. This typically happens in 1st and 2nd. Also, cruising at highway speeds in 5th or 6th....if I got on the gas the car would move with pretty good acceleration. Now, not so much. Something just does not seem right.

Could it be a spark plug misfiring, in which it needs to be replace or something else mechanical?

Also, my downshifts are not as loud as they used to be. I mean, I can understand the engine being quieter from the oil but the exhaust note should still sound the same, right?

If you try to get on it under 3k or so you will feel a sudden power surge at some point becuase there is absolutely nothing down there.

Well, I swear that prior to this week, the TQ curve felt more linear than now. Like there wasn't such a sudden surge, like you said. I don't know perhaps it's a combination of the reduced engine noise and the little bit of added performance from the RL oil that is making it feel differently. But still, the car feels hesitant under 3K or so. It didn't feel that way before......strange.

Reset your ECU......(disconnect the Neg. Bat. terminal for a few minutes, or do a search for the reset procedure)

Chech your oil level. If you accidental put too much in , it could reduce engine power.

I checked the oil level a couple times. A few on the day of the oil change and again the day after. The level is in between the two punch holes. It's like 3/4 from the bottom punch hole to the top one. Anywhere between those two holes is fine.

^OK. Scratch my idea off the list.:tiphat:

^^ Yup...thanks though. I appreciate the help.

My car is like this also, always has been though. This engine just doesn't have a ton of low end torque. Its the main reason why I think a supercharger will be best for the car instead of the twin turbo.

**Please don't misunderstand my comment, I'm not saying this engine sucks. I love my car, and think is super fast.**

If you're confident that the problem is isolated to the oil change, do the following:

1. check the oil level and make sure its full (but not overfilled). If you're low on oil (significantly), it could affect the VVEL system as it relies on oil pressure.

2. check all the parts you touched. Did you accidentally knock off any hoses or air tubes from the engine while working on the car? Is the dipstick inserted all the way in? Leaving it slightly out, creates a minor vacuum leak.

3. What oil weight did you use? If you used the wrong weight (typically too thick) it could create a small drag on the engine parts and decrease HP. Nissan recommends 5w30.

4. Very unlikely, but you could have a defective (broken) filter which isn't allowing enough flow. Are there any dents in the filter? The bypass mechanism could also be stuck. Its driven by oil pressure and at 3 - 4K RPM most oil filters fully bypass for maximum flow.

Basically, go through every step you did and make sure its right. If its all done correctly, and you still have the problem, I doubt its the oil change. I hate to ask, but did you do anything else other than the oil change?

Good luck and update us.

Fix for sluggish acceleration
 

I had the same problem, starting this spring. I found that if I reset the ECU by disconnecting the battery, everything resets and the car runs really well for approximately ninety days. I repeated the procedure when the sluggishness returned, and the problem was corrected.

Several other things noted:
I run Red Line 5w-30 exclusively, and make sure its always topped off, as I noticed similar symptoms when the oil is not full. I switched to Red Line after reading all the posts on high oil temps. Red Line synthetic will easily handle the higher temperature requirements and contains ester, as recommended by Nissan.

I also noticed that the ECU seems to have issues if I switch gasoline vendors, so I use Shell exclusively.

I replaced the air filters at 10K since we've had a horrific winter with much dust from the sand left over on account of the snow plowing efforts.

Aside from the periodic ECU reset, the car operates really well.

Interestingly, an ECU reset DOES improve things for a while (for me, it hasn't been anywhere close to 90 days), before it reverts to the same old same old. I wonder if it's just long enough for the ECU to develop the long term fuel trims?

I think the cAr just doesn't like intakes. Ever since the injen intakes the cars been running crappy in the lower rpms. It's much better after the tune but when it's real hot out the cars like bla under 3k then when it hits about 3.5k the car takes off

I'm thinking this might be the case. Though I believe the OP is stock...

I should probably put the factory intakes back on and see if I can tell a difference.

DO it up and let me know