# Loss of power



## Tommy A (Nov 27, 2004)

Hi all!!
First post on this board.
I have a 97 Maxima 5 speed with 120k. The car has been trouble free and very well maintained. The past few months I have been experiencing luck of power on acceleration.
It came gradually so I didn’t really notice it until last week when it started running fine for a few days. While I accelerate on all gears it feels like the brakes are applied (pulsate) up until the 3k rpm range. After that it opens up. No engine light and no codes. Always premium gas. All the filters have been replaced.
Any help will be greatly appreciated.
Tommy A


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## brianw (Feb 25, 2004)

Check the TPS resistance and MAF voltage?


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## MaxQuest (Sep 11, 2004)

Check for codes. You might need to change your Knock sensor.


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## Tommy A (Nov 27, 2004)

Thanks for the responses. Since first posted, 5 different Nissan dealerships had a look at the car and nobody could figure out the cause. No codes and all sensors have been checked fine. They suggested contaminated fuel (water). Since the beginning of December I have been using 2 cans of dry gas per thankful with no positive results. Today the vehicle was at another Nissan shop. I was told that a probable cause is the wiring harness that connects to the passenger side of the fire wall. Cost near1k. The tech is also a good friend and was told that it could go away for no reason. He treated the full with 2 cans of octane booster. Nissan is recommending it after doing a fuel injection service. No difference for the first 1 hour of driving. All of a sudden the engine opened up. It started accelerating freely and recovered the entire lost HP. Not sure what happened but loving it. 
Does anybody have any thoughts on this??
Tommy A


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## deadmax96 (Dec 2, 2004)

thats a good queston cause I am somewhat experienceing the same with my 96, however I can feel lack of power in the lower rpm's but once I reach about between 37-3900 rpm it opens up. It is pretty much almost through all gears. I did a full tune-up (without changing belts) did fuel filter, plugs, air filter, oil& oil filter, changed remaining fluids, also added fuel additive I think it was lucas, with throttlebody cleaner also, o2 sensors. I have looked at the ecu no codes are being thrown for this reason. I don't know, what exactly did your freind do besides the octane boost?? maybe that will help me out. strting to get me PO'd.


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## Tommy A (Nov 27, 2004)

Deadmax96,
My car was doing the exact same thing as your car.
Just an update since the quick fix. After burning all the treated gas, I refueled with out any additives. The car started acting funny again immediately. Frustrated I stopped at a local auto parts store and got some octane booster. The car within 2 minutes was running much better. Very slight under power but not as good as when treated with the recommended additive. Please don’t waste your money replacing parts. What worry’s me is the wiring harness. According to many Nissan techs it’s not unusual to find it as the cause of the problem. It’s the engine movement that’s causing to go bad. Most of the time with out any engine codes. I will try to get some more additive from Nissan and update you.


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## PhaTeLeSS (Oct 22, 2004)

somehow the wiring harness and octane booster just don't add up to me. why would octane booster make any difference? do these cars have computer controlled timing? i've heard that nissane injectors tend to go bad around this mileage, could that be the cause? good luck guys!


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## MaxQuest (Sep 11, 2004)

I doubt that the octane boost had anything to do with getting his power back. It was more likely from the fuel injection cleaning and finally getting some good gas to the engine. All that dry gas and other additives was making things worse.
The only computerised timing we have is that if there is knock then timing will be lowered a few degrees. It will stay lowered for a while before the CPU will go back to its normal advanced timing.


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## Tommy A (Nov 27, 2004)

Maxquest,
I did not clean the fuel injection system. All techs that inspected the vehicle agreed that it doesn't need it. The vehicle always gets premium gas. I have tried refueling from different gas station with out any luck. The only thing that was done is just add the booster. I will try it again over the weekend and update. It’s very frustrating having such problem and not being able to find the cause. Just trying different thing right now to see what will correct the problem.


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## JimN4BYO (Dec 8, 2004)

*Fuel additive corrects wiring harness problem -Hmmmm*

Wow, that seems strange-until you think about it some.
Suppose a bad connection/wire sends a signal to the engine telling it to run the engine advanced as far as possible. 
That will do the following:
1. lean burn
2. knock sensor activates
3. Power is lost.

Increase the Octane (add antiknock agent - can be 5W oil for the same effect). Then what happens....
1. Richens the burn
2. kills knock sensor
3. Restores power
Effectively, compensating for the bad signal going to the engine.

The above may be unlikely - but it is an interesting theory.

Additives to reduce knock (Octane boosters) can be expensive or cheap.
Suggest trying 5 weight oil (start with 2 ounces per 10 gallons of regular gas). It is used in marine engines, old "leaded" gas engines and in some small airplane engines.


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## Tommy A (Nov 27, 2004)

*Finally check engine light*

Finally the check engine light came on as the vehicle was running full power with booster in the tank.
FRT/LEFT o2
KNOCK SENSOR
FRT/RIGHT o2
FUEL INJECTION R/BANK LEAN

Where do you start??


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## Tommy A (Nov 27, 2004)

*Agree with the theory!!!*



JimN4BYO said:


> Wow, that seems strange-until you think about it some.
> Suppose a bad connection/wire sends a signal to the engine telling it to run the engine advanced as far as possible.
> That will do the following:
> 1. lean burn
> ...


Jim,
My scenario is closer to the first theory except I am running very high octane right now and the engine is producing a lot of power.

I like your approach!!


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## deadmax96 (Dec 2, 2004)

okay ingards for the lack of fuel, brought the car to the dealer.....Had the car diagnosed no evidence of bad fuel, however two injectors was misfiring (according to him). Still no codes were being thrown out from the ECU. Ha dthe injecotrs replaced, i NOTICED that the car was getting power back however I am now experiencing mad fuel lose. Like i already stated I did a full tune up (except belts). Throttlebody cleaner, and switched up to syntech 10W30. now I am getting a little adjetated abut this whole thing!! I asked the dealer he was really no help he told me that they can look at the car but my warrenty with the dealership won't cover it. I am thinking of just ripping the whol fuel rail and harness out and seeing if I can try to pinpoint the problems. If anybody knows of what might be doing this, please please help me out!!


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## Tommy A (Nov 27, 2004)

deadmax96 
I know how frustrating it is. After 3 treatments with octane booster I decided to just refuel with out any additives. The car is starting to run much better on its own. Still some slight hesitation up to 2200 rpm but it has improved greatly. It’s not pleasant when shifting from one gear to another and not being able to accelerate. For now use some octane booster. You will see great results. If it matters it’s on sale at 
Advance auto parts. Please take my advise and stop spending unnecessary $$$$$ on repairs. I use 2 fuel tanks a week. We’ll get to the bottom of it. As for my check engine light, a thorough test of all the sensors by Nissan proved that there is nothing wrong yet. I was beating the leaving hell out of my car with large quantities of booster in the tank (taking out my frustrations at 6500 rpms between gears).


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## Tommy A (Nov 27, 2004)

deadmax96 said:


> okay ingards for the lack of fuel, brought the car to the dealer.....Had the car diagnosed no evidence of bad fuel, however two injectors was misfiring (according to him). Still no codes were being thrown out from the ECU. Ha dthe injecotrs replaced, i NOTICED that the car was getting power back however I am now experiencing mad fuel lose. Like i already stated I did a full tune up (except belts). Throttlebody cleaner, and switched up to syntech 10W30. now I am getting a little adjetated abut this whole thing!! I asked the dealer he was really no help he told me that they can look at the car but my warrenty with the dealership won't cover it. I am thinking of just ripping the whol fuel rail and harness out and seeing if I can try to pinpoint the problems. If anybody knows of what might be doing this, please please help me out!!


As for the oil it doesn't make any difference. Please note that a 5w 30 or 10w 30 will have the same viscosity once the oil reaches normal operating temperatures. The only advantage is on start up but will not help resolve the problem.


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## deadmax96 (Dec 2, 2004)

tommyA
Thanks, yeah I had no choice but to bring her into the shop due to the injectors. Other than that I am going to buy some octane boost and see what that does!! Hopefully I will figure this out and have some way to resolve and maybe put it as a sticky for future refferance!! Other than that I am still not trying to get to pissed off about it, jsut really frustrated!! But thanks though. Let me know if you ever uncover anything in regards for the situation! That would be really helpdful!!

drew


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