2002 Nissan Sentra Loss of power

Tiny
DIVER76
  • MEMBER
  • 2002 NISSAN SENTRA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 14,000 MILES
I have a 02 Sentra w/140,000 miles. About 2 months ago I began to feel a slight inconsistency while accelerating & when I came off the gas. The problem has worsened severely. My vehicle now eats gas, has severe power loss & has allot of trouble climbing hills. The car cannot be driven at this point. The vehicle idles perfectly & the problem only happens when the vehicle is being driven. We have checked the catalytic converter & it's fine, checked all hoses for leaks, checked the fresh air intake, & air filter. No problems found there. My question is what could this be? I took it to my local Nissan dealership to have it diagnosed but what they advised as the problem doesn’t make to much sense & the price is outrageous for the repairs over $1,000.00. What could the problem be? We also replaced the spark plugs in Dec of 09 & they are needing to be replaced again. Thanks
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Saturday, February 6th, 2010 AT 12:02 PM

7 Replies

Tiny
MATHIASO
  • MEMBER
Hello diver76

Welcome to 2carpros. Com

Check your spark plugs.

A single fouled spark plug is bad news because it can kill up to 25% of a four cylinder engines power
output. It is like riding a horse with a broken leg. A fouled plug will also cause a big increase in fuel consumption and emissions.
You changed the spark plugs in December, if there are needing to be replaced again, we should find the cause.
Fouling can be a problem if an engine uses oil. Worn valve guide seals and guides can allow oil to be sucked down the guides and into the combustion chamber. A heavy buildup of thick black deposits on the plug and intake valve
would indicate such a problem. Worn or broken rings, or damage to the cylinder wall can also allow oil to enter the combustion chamber and form ash deposits on the plugs.
If your engine is not using lot of oil then the cause must be something else.
Extensive idling and/or short trip stop and go driving can also lead to a rapid buildup of normal fuel deposits. This occurs because the plugs never get hot enough to burn off the deposits, something which plugs are designed to do or a powdery black deposits on the plugs can occur from "carbon fouling." The underlying cause here is a rich fuel mixture. The problem might be a leaky injector, or a dead oxygen sensor or coolant sensor that prevents the engine control system from going into closed loop and leaning out the fuel mixture.
If this does not answer your concern or If you have engine code please provide it, if no code let me know
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Sunday, February 7th, 2010 AT 8:56 AM
Tiny
DIVER76
  • MEMBER
I had plugs looked at yesterday, there ok & there is no carbon build & no oil consumption. I went based on the dealership's advice. I don't have a miss it is power loss. We checked the MAS, & a few other sensor by testing them with a ohm meter. What we did check seemed ok. When we started yesterday to trouble shoot it was giving us a code P0128 (Coolant Thermostat). After checking some things & went for a test drive the we checked codes again & now have no codes but do still have the problem. To help with what we have found is the car runs better while very cold. After just a to mile the problem appears. I hope that's enough information. If you need specifics please let us know so we can help you out. I want to share with you what the Nissan dealership said was wrong with my car but I want to hear everything you think it could be first. I hope you understand. Everyone I have talked to said that what the dealership said needed to be fixed is just outrageous & crazy. Thanks again for your time & help.
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Sunday, February 7th, 2010 AT 11:56 AM
Tiny
MATHIASO
  • MEMBER
Hello diver76

Thank you for providing more information.

The code P0128 means that the engine's
PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. The intent of the P0128 code is to indicate a faulty thermostat. Similar codes: P0125

In determining the engine did not reach a "normal" temperature, it takes into account the length of time the vehicle has been running, the intake air temperature (IAT) sensor reading, the engine coolant temperature (ECT) sensor reading, and the speed of the vehicle.
Depending on the nature of the fault, the lamp may come on and go off, remain on continuously or flash. Some types of intermittent faults will make the lamp come on only while the fault is occurring. When the fault goes away, the lamp goes off. Other types of problems will turn the light on, and it will remain on until the fault is diagnosed and repaired.
Here is the list of things to check:

Verify coolant strength & level
Verify proper cooling fan operation (check if it's running more than it should). Replace if necessary.
Verify proper engine coolant temperature (ECT) sensor operation, replace if necessary.
Verify proper intake air temperature (IAT) sensor operation, replace if necessary.
If the above items check out good, replace the thermostat
Your vehicle is a Nissan The ECM may need to be reprogrammed to correct the P0128 code.
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Sunday, February 7th, 2010 AT 2:39 PM
Tiny
DIVER76
  • MEMBER
Ok, here's what the dealer ship said was wrong. My timing chain was severly worn & needed replacement. Along with that the tensioner, guide, & so forth. What's your take on this? Not sure where to turn. Everyone is just looking at the car & scratching there head!
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Sunday, February 7th, 2010 AT 5:52 PM
Tiny
MATHIASO
  • MEMBER
Hello diver76

if timing chain is lose, you will hear some ticking, rattling noise while engine is running.
Loss of engine power have something to do with the code p0128.
Dealer knows what noise is for which defective part.
He may be right, or he may be wrong.
Anything about replacing timing chain comes as a sett.
That involves replacing other parts that work together with the defective part just to do a good job.
The loss of power have something to do with the code p0128, remember that. Lose timing chain will make some noise.
If you hear ticking, rattling noise than the dealer maybe right. The dealer may be right also if timing may get bad in the nearest future or base on" timing chain should be replace every 100.000 miles as preventive maintenance", then it does not solve the problem for which the engine is losing power.
That should be optional not because there is 140.000 on your vehicle.
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Sunday, February 7th, 2010 AT 9:26 PM
Tiny
DIVER76
  • MEMBER
There is no rattling my engine is quiet & idles great Just the loss of power. I changed out the Coolant Temperature Sensor & I still have the problem now what? Is that the part you wer etalking about? Thanks
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Monday, February 8th, 2010 AT 3:49 PM
Tiny
MATHIASO
  • MEMBER
I gave you a list of sensors to check. You should also contact your dealer about reprogramming the computer.
There was TSB about reprogramming the pcm when the code p0128 is shown for Nissan
you can do this as last result.
Before that, did you check the thermostat? The IAT?
Check those and get back to the dealer.
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Tuesday, February 9th, 2010 AT 2:26 AM

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