Questions and Answers
Nissan Maxima No High Idle, Runs Rough
Q. Vincent, I have a 1985 Nissan Maxima with a 3.0 liter V-6 and 225,000 miles. The initial problem that I have is that my car lopes and stumbles a lot when I first crank the car in the morning.There is no noticeable fast idle present.
If I take off before the car has completely warmed up, by the way takes about 10 minutes, the car will cough and spit before finally taking off. this will also continue until warm up. I have changed the air and fuel filter and nothing seems to help. The plugs and wires have also been changed.
Also, at times, the car will idle erratically after it has warmed up. Most of the time it happens during re-start. Usually I have to get on the gas to clear the problem. Other times the car will not start without pumping the gas, or the car has to sit a few minutes before it will re-start.
Overall the car is in decent mechanical shape other than needing struts. How can I solve these problems without putting a hole in my pocket.
A. When you replaced the spark plugs, did you use NGK spark plugs? Nissan's are fussy about their spark plugs and they run best with NGK plugs in them. Your engine requires NGK BCPR6ES-11 gapped at 0.039" - 0.043".
When you replaced the ignition wires, did you install a new distributor cap and rotor. This engine goes through them fairly quickly.
After that, I would give the throttle body a good cleaning. A dirty throttle body will cause all kinds of idle problems and often a cleaning will fix them. Read DIY: Cleaning Throttle Bodies to learn how to do a good cleaning.
There are a couple of other things to check for as well. One is the Coolant Temperature Sensor (CTS). If the CTS is telling the PCM the engine is hotter than it actually is, the PCM will lean the fuel mixture and this will cause idle problems.
A fuel pressure and volume test will tell if the fuel pump is doing it's job supplying the engine with the proper pressure and volume of fuel that it needs to run smoothly.