I know this subject has been beaten to death, but I am having a problem with my 2000 SE 5sp. It seems like something is really holding the car back under hard acceleration, especially noticable after shifting to 2nd. The CEL is not on. I also have a 97 5sp, so I have something to compare it to. I know the 2000 is heavier than the 97, but something is just not right. Would the VIAS cause this to happen, or does that only affect things after 5000 rpm?Throttle body has been cleaned, and maf replaced along with ecu reprogram. Still manages to get 25mpg, so if the problem is fuel related, the gas mileage isn't suffering. Any helpful suggestions would be greatly appreciated.

 

Is this similiar to my problem? I am hoping someone will have some insight for me!

I had the idle stalling problem so I cleaned the throttle body as recommended in another discussion which caused a CEL. After wiping the outside clean, I sprayed TB cleaner into the TB while revving it while the car was running (as indicated on the TB cleaner label). Eventually the car died and wouldn't start again.

I hooked everything back up and the car started and now idled great! But, when I gave it more than 50% throttle it feels like there's actually less power than at 50%. I unplugged the battery for over an hour to reset the CEL and ECU (I think?). Same problem - give it more than 50% throttle and it's gutless. And if I floor it in 1st it will hesitate a lot at 4K before continuing to accelerate at a pitiful pace. Idle is great though :-|

I have driven the car 30 miles or so on freeway, around town, and shut it off and drove it again about 3 times.

Please help!!

Thanks!

Jason

 

Is the idle stable and correct or is the throttle "hanging". Did you disconnect any connector on the TB or disturb anything on the TB? If during the TB cleaning that you find that it was really gummed up (and I suspect with your MT, it probably was) it's a good idea to do an Idle Air Volume Learning afterwards.

 

Thanks for your reply. My throttle is good now - it's not hanging. It sits at 700 rpm (or whatever it idles at nicely - can't remember off the top of my head).

I didn't disconnect any wires or anything - I just took the 4 bolts off for my airbox so I could get at the TB.

I have a 2000 Maxima - so isn't disconnecting the battery to reset the ECU the only thing I can do? I thought the air volume learning was for 2002 Maxima?

What does MT stand for?

Thanks again for your response - I really appreciate it!

Jason

 

Glad my thread can be used by others to ask for help with their problems.

 

the vias only activates at 5k rpms when its working but if it breaks then it could break in the open position like being above 5k rpms, closed position like below 5rpms or somewhere in between where it can do what it wants. if its broken closed then top end suffers greatly, if broken in the open position then low and midrange torque suffers.
i would be curious about other maintenanace since you mentioned a few things. how is the condition of the air filter or the plugs? the easiest way to see if it down on power is a dyno. for 45 bucks or so, you could 3 pulls with a/f depending on the shops around you and know within 15 minutes if the power is low and what rpm its happening in.

 

Thanks for the reply. Air filter is good and plugs were changed soon after the car was bought. It had 78,000 miles when I bought it and now has 94,000. I think the lack of power was present when I bought the car, but I didn't pay much attention to it then. My wife usually drives the car and we went on vacation this past weekend and I knew after a few take offs that something was not right. Is there any way to check if the VIAS is broken in the open position? The difference in power/torque between my stock 97 and my wife's 2000 is very evident. One more question......is it possible to have a bad coil and have no codes, perfect idle, and avg. of 23-25mpg?

 

for the dyno.

 

I seriously doubt a coil would be bad and not either cause a rough idle and shaking or when it misfired that it would not throw a cel. from how well the car seems to drive otherwise, it would let me to believe the power valve in the vias is broken from the cup or holding on by a strand. there are writeups floating around here about opening up and checking the vias function but a dyno is the quickest and my opinion the easiest. some shops may even have a dyno day where you could get it cheaper than i stated before.

 

Had the same thing as both of you described. What fixed it for me was a new gasket around IACV. I tooked it out once before to clean it and put it back, then during about 9 monhs I noticed the loss of power. Took the IACV out again and noticed that gasket was letting air and coolant get into the intake. The original gasket sucks once you take it out. The chamber from the IACV right behing butterly was full of green hard wax-looking crap from the coolant line. (Coolant runs through IACV for whatever reason.) So I cleaned it, used silicone gasket maker and re-installed IACV back again.

That sure did the trick for me.
Try it.

 

I, too, have been having a similar problem. I have a 2000 MT SE. It always seemed to have a small power gap around 3000 RPMs, but that seemed normal. But now the power comes and goes at random. Sometimes it's fine, sometimes it really lags and it's not consistent with the RPMs that it happens at, other than it >usually< cuts out at 3000. I too have no SES light and tried reseting the ECU. Any ideas? I'm wondering if it could be the VIAS, but would that cause it to come and go like that?

About the gasket, what is IACV? It could have something to do with that since I had to remove some of the intake components to get to some other components I was working on recently.

 

I'd start with the VIAS, the catalytic converter or an O2 sensor.

 

IDLE AIR CONTROL VALVE (IAC)
An electrically-operated valve which allows air to bypass the throttle plate in a fuel injected engine to regulate engine idle speed.

 

Would a bad catalytic converter or O2 sensor affect gas mileage? Thank you and everyone else for the replies. Any other suggestions would be greatly appreciated.

 

both can, but I didn't notice a change in gas milage when mine went.

 

Did your catalytic converter and your O2 go bad? Did your car react similar to the way as mine? Also, is there a way to check for a bad catalytic converter and O2 sensor without a cel?

I don't know if an earlier problem I had could be related to my current problem. About a year ago, the rpm's would fall below idle when coming to a stop and sometimes causing the car to die. After reading, I cleaned the throttle body with throttle body cleaner. Instead of removing the throttle body, I cleaned the throttle body and eventually went through a whole can. I sprayed the throttle body cleaner directly into the throttle body with the butterfly flipped up, wiping occasionally. Soon afterwards, the maf went bad. Anyways, could I have screwed something up and contributed to my current problem?

Sorry for all the questions. Thanks again.

 

Anyone know the answers to the questions above?

 

I'm as in the dark as you.

I'm taking my car to the dealer this Thursday. If the thread isn't dead by then, I'll post what they say. This weekend I'll probably try a few things like checking out the IACV and the O2 sensor. Hopefully I can fix it and post what worked, this is a frustrating problem. So many things it could be...

 

OK, whitemax, here's another possibility. I unplugged my intake air temperature sensor and the problem went away completely! So it was either a bad sensor or a bad connection to it. I tried that since I had to unplug it and plug it back in while in the process of doing some work where I had to remove the intake duct, and that's when the problem started. Anyways, something for you to maybe check out.

Oh, and about that MAF question, the MAF sensor comes before the throttle body, so I don't see how what you did could have affected it. Must have just been coincidence.

 

unplugging your iat sensor fixed your lack of power problem? did you leave it unplugged?

 

I don't see an O2 affecting performance

 

the primary o2 sensors at partial throttle are responsible for setting air fuel ratio along with the maf. at wot, the maf takes completely over. with the primary o2 sensors affecting a/f, it can certainly affect power.