Hi,

I'm really getting sick of this. Every morning i will drive the car & it's accelerating OK, But afternoon when i'm back from work ( The outside temperature is about 120 F ), The car is totally losing power & it does not matter how hard the gas pedal will be pushed, The RPM is hardly going over 3000 RPM !!!

The car is not overheating at all and the temperature gauge is showing that it's OK.

Please help ...

 

It sounds like you've identified the culprit.

Are you using a name-brand, premium grade fuel or the cheapest stuff you can find or non-premium gasoline? If the knock sensor detects pinging in your engine, it will pull timing which results in a power loss.

What about water temp, is it higher than normal? That too can put the car in safe mode and cause a drop in power and limit to RPM.

 

This Z is going into a limp mode for some reason. How about a complete diagnostics at Nissan.

 

I'm using 98 octane fuel, which is the best in my area.



The picture shows the maximum temperature that the coolant will reach before the thermostat opens & fans start to work & ithink it's OK !

I'm trying to figure out the problem may be it can be fixed. But i will be diagnosing the car at nissan if the problem remains.

Some more info,

I use Castrol Edge Sport 10W-60 fully synthesized, Now it's almost 3.5K Miles since my last oil change.

I replaced my air filter last week hoping that it will help but no luck.

I checked under the hood & i could not detect any leaks or bad thing .

Ideas will be appreciated, Thanks...

 

its probably because it's 120 degrees out....

 

Do you think that it's normal ???, I really doubt !

 

extreme heat such as 120 will cause power losses.

 

One thing that i'm sure about is, It ONLY happens afternoon when it's the highest temperature of the day.

But, What the heat will affect exactly, I mean should i change my engine oil, gear oil or my engine coolant cause they are the ones getting affected?

do i need an oil cooler for example?

I'm really disappointed, Please help ....

 

hot air outside will mean the cars intake is also sucking in hot air... the hot air will somewhat bog down the engine, and cause said performance loss. if you've noticed the colder it gets, the quicker the car also gets because of the cold air being sucked in

 

but as far as it being normal, yes i'd say it is. and if you're not overheating or noticing any other heat issues, then it sounds like all is normal. maybe try not pinning it everywhere too...

 

my car feels sluggish in 100 degree weather... its normal.

 

your ECU takes into consideration air temp. It adjusts your timing and fueling accordingly. Hot air is less dense = richer mixture. richer = less power.

 

Since we don't known exactly where "On Earth" is located, it's hard to nail a diagnosis down the definitely being just the air temperature. If you're talking about a thermometer reading of 120, the air inlet temp on your can can easily be 130+, especially if you're driving on a black-top road in slow moving traffic.

If the temperature gauge reading you showed is the max you are getting, then something is truly wrong. Mine goes to the half-way point on any normal day. If you have a coolant system problem, the gauge may be reading low where the water temperature is really higher. Again, something that could cause a loss of power.


You need to get it hooked up to the Nissan Consult system and checked out.

 

^^correct. Normal coolant temp should read about middle/just below middle on the stock coolant temp guage.

 

That's interesting , I was thinking that my cooling system is working as it should!
My Temp gauge will be (always) like this when i'm driving on the high way:



Thermostat issue or the gauge is sending false reading ?

 

A stuck thermostat would cause the car to overheat, and the gauge would likely read high.

A defective temperature sensor would cause the ECU to think the car was not warmed up, but may be confused by other signs that it should be hot (i.e. intake air temp). That confusion in signals could throw the car into safe mode.

 

Couldnt it be possible that the thermostat is stuck open and not allowing the car to warm up? As far as your car going into safe mod, I am guessing it could be a sesor issue as well. +1 on diagnostics.

 

i turned the car on this morning, But the fans didn't work directly. It only did when i started the A/C. Meaning the thermostat is O.K?

I tried the car this morning & it was pulling great, The A/C was ON & VDC ON.
I will try this afternoon to turn VDC OFF & push the car.

By the way, will it be helpful to check the ecu for error code?, it's damn expensive here.

 

Wanted to know if there's something wrong or no, I diagnosed the car & it returned no error codes , The ECU last reset was 1.5k Miles before.

What you people think, i'm sure that it's not something in my mind .

 

It's not going to throw a code for a stuck thermostat, defective temperature sensor, etc.