Nissan Repair: 1995 Quest ruff idle, mass airflow sensor, coolant temperature sensor

Question
QUESTION: Hi i have a 1995 quest is hard to start but when it start it idle ruff but it does it only when the check eng light is on but if the light goes out it drives like a dream another thing is that if the eng is off but the key is on and you step on throttle the rpm guage goes to 4000 rpm and it there is a clicking sound under the hood it get louder when you step on the throttle

ANSWER: Hi George -

Have you diagnosed the code for the check engine light? That will narrow the problem down tremendously. It is called an OBD (On Board Diagnosis). I think Autozone will check that for free. There are literally hundreds of codes, so doing this would be a great first step.

Let me know what the number is, and then we can start from there -

Hope this helps -
aloha
Calvin

---------- FOLLOW-UP ----------

QUESTION: Hi the eng code is 55  and i check it and auto zone has check it on many times there is no other code

Answer
Hi George -

Hmm. there is no such code as 55. The prefix for each code is "P" and it ranges from P0100 all the way to P1899.

Please check the production date on your vehicle (or look at the sticker in the engine compartment. If it was manufactured in early 1995, you could have an older ECU and the codes are different - as follows:

Code 11 Crank sensor angle

Code 12 Mass airflow sensor

Code 13 Engine coolant temperature sensor

Code 14 Vehicle speed sensor

Code 21 No ignition reference

Code 22 Fuel pump

Code 31 Engine control unit

Code 32 EGR sensor

Code 33 Oxygen sensor

Code 34 Knock sensor

Code 35 EGR temperature sensor

Code 43 Throttle position sensor

Code 45 Injector leak

Code 51 Injector circuit

Code 54 Automatic transmission signal

Code 55 No malfunction recorded

However, if you look above, code 55 means no malfunction present. Remove the negative battery cable for a few minutes, and this should reset the check engine light. If you drive around and the light is still on, then you should have it re-diagnosed.

Hope this helps -
aloha
Calvin