Power Loss

Tiny
DAMAIOSHIN
  • MEMBER
  • NISSAN ALTIMA
Recently, my 1998 Nissan Altima GLE has been running poorer than i'd like, and it isnt a gradual change, it seemed to happen after I changed the spark plugs.

It has 120,000 miles and never has had a problem before.

I am having significant power loss, esp. On the highway. Where normally it runs around 2.5k RPMs at 70mph, it now run at 3k. Not to mention accelerating to merge onto the interstate often redlines it.

My service engine light is not on, so I have nothing to go off of there. I did an oil change, sparkplug and sparkplug wire replacement. I also replaced the top O2 sensor but could not get the bottom, I did this mainly as preventive maintenance as my care has over 100k miles and never had them changed. Nothing seemed to help the problem.

Any suggestions would greatly help, I drive over 1000 miles every 2 weeks on long interstate stretches and cant afford to pay the gas while running at high RPMs like that.

Thank you very much to anyone who can help me.
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Friday, October 5th, 2007 AT 1:01 PM

7 Replies

Tiny
JACK42
  • MEMBER
First look real close to see if you knocked off any vacuum lines or anything else like that. What kind of plugs and wires did you use? Does it idle smooth? Did you check the gap on the plugs before you installed them?
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Saturday, October 6th, 2007 AT 8:27 AM
Tiny
DAMAIOSHIN
  • MEMBER
I will check the lines this morning. But to answer your questions: I used Bosch Platinum +2 so there was no need to gap.

The wires are Duralast. (Note: I changed the spark plug wires after I noticed the problem in hopes it would help)

As for the idle, it idles smooth, but high: 1k RPMs in gear. Its usually between 600-750.

I was wondering, could there be error codes without the CEL coming on?

Thank you for your response!
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Saturday, October 6th, 2007 AT 8:41 AM
Tiny
DAMAIOSHIN
  • MEMBER
I've checked all the lines and nothing looks out of the ordinary.

I have also noticed that when I turn my engine off, my exhaust makes a sort of putter sound. Almost like a growl or flapping rubber. Its hard to describe.
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Saturday, October 6th, 2007 AT 9:45 AM
Tiny
JACK42
  • MEMBER
Worst plugs on the market. Install whatever the OEM plugs were.
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Sunday, October 7th, 2007 AT 7:55 AM
Tiny
DAMAIOSHIN
  • MEMBER
New, normal spark plugs installed (NGK: FR5AP-10, gapped to.40). I took it for a test drive and no change. And my local mechanic doesnt seem to want to do anything b/c of no error codes.

Thank you very much for working with me about this.
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Sunday, October 7th, 2007 AT 10:46 AM
Tiny
JACK42
  • MEMBER
Automatic trans or stick? Is it possibly like the trans is slipping a little? Could be a slightly plugged exhaust. Without any codes to go by, this wil be difficult
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Monday, October 8th, 2007 AT 7:00 AM
Tiny
DAMAIOSHIN
  • MEMBER
It’s an automatic. And I considered the trans as well, but the RPMs stay high in neutral idle as well, which would lead me to think that it is probably not the transmission.

Plugged exhaust could be a possibility. Maybe account for the put-put when I turn the engine off. How would I go about checking that?

And it is definitely hard trying to go about this without errors codes. And without spending alot of money on unneeded parts just to go through the checklist.

But thanks a lot for trying to help me. It is not unappreciated.

I was wondering (and hoping not) if it could be a problem with fuel pump?
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Monday, October 8th, 2007 AT 11:17 AM

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