# 1995 Nissan maxima problems



## maanave (Jul 14, 2012)

I have a 1995 Nissan maxima that runs perfect. It has 192,000 miles and a great pickup. I have been using royal purple oil regularly from last eight years every 3000k. I maintained it pretty good. From the last couple of years, I started with a couple of problems.
1- Engine light occasionally comes on while driving. The light comes on more frequently during hot weather. I took it to the different shops, and they told me about 3 different codes.
•	Knock sensor 
•	Temperature/Coolant sensor
•	O2 sensor 
So, I replaced all of them. However, the most frustrating part is even after replacing all the sensor, two days later light came back on again, and I was told the same thing means the same codes.
I need help. 
2- The most serious problem and that is driving me crazy. I took the car to various shops and explain them the problem, but they could help me because it does not happen all the time. 
90% of the time the car starts good in the morning. I go to the office with no problem. I park my car in the opened parking lot under the sun.
During my lunch break if I go out, 90% of the time, it will start okay, but if I drive 5 to 10 miles and park, and when I come back it would not start. 
The only way it starts, if I take a very long ignition self (at least a minute without any interruption) while pressing the gas paddle, it will start, first with the coughing and a minute later it will run okay.
I used to have this problem this occasionally now every other day.
I cannot let my wife drive the car with my children, because I know she will not be able to start the car.
Please help


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## smj999smj (Jan 1, 2006)

As far as the codes, anytime a knock sensor code comes up with other codes, it's often not the knock sensor that's a problem. Also, just because a code for a part is set, it is not necessarily the part itself that has failed. Trouble codes aren't designed to tell you what the problem is, but only to help you identify what system has been detected by the ECM as having a problem. Then, one can use the code to determine which diagnostic procedure one must follow to properly diagnose and isolate the true cause of the problem. Yes, an O2 sensor code is often due to a faulty O2 sensor, but it could also be caused by a number of other things, including an excessive lean or rich mixture or an electical circuit issue or exhaust leak. Auto mechanics often play the odd by replacing the sensor associated with the trouble code, by a good auto technician will diagnose the problem, first. If the codes were erased when the new parts were installed, then the ECM should be checked to see what current trouble codes exist and then diagnosed accordingly.

As far as the starting problem, there are a couple of things to look at. First, make sure the engine is not due for a tune-up and proper type NGK spark plugs are installed. By your description, it sounds like the engine is loading up with fuel. Leaking fuel injectors are not unheard of and a fuel pressure leakdown test would be in order (testing for proper fuel pressure should also be done, since a fuel pressure guage will be needed to test for leakdown). If one or more injectors are leaking down, when the engine is cranked, the fuel can foul the spark plugs and make for a hard start. Another possibility could be a faulty IACV-AAC valve or improper base idle setting (which is needed for proper operation of the IACV-AAC valve). The valve controls an an airport to help with cold start fast idle and maintaining idle under a load. The valve can become built or with carbon or simply fail altogether.


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