I have a 98 Maxima manual trans. I bought it with 187,000 miles. At that time it had a slight miss. It wasn't much of a concern because it wasn't that noticable. It is obvious when starting as it acts like the timing is off. The engine cranks and hesitates like a small block chevy with the timing too far retarded.

Over the last few years I've replaced all spark plugs, all fuel injectors, and 4 out of 6 coils. I've tested the coils by unplugging when idling and all make a significant difference when unplugged. I thought I had the problem resolved when I replaced the last coil. The car runs great when cold now. It still hesitates when cranking but when it's running cold it doesn't miss at all. As it warms, the problem comes back and it gets worse at it continues to warm and worse still when under load.

I have tested the MAF and I get battery voltage on the red wire and 1.06 ohms on the white wire while idling. I also cleaned the MAF. No change.

I pulled trouble codes and had a 0701 and 0201. I cleared the codes and restarted the car. When it hesitated during cranking, it threw the 0201 again.

I only want to sell this car. If it were possible to make it run the way it does when it's cold all the time by doing some rigging, I'd do that. However I don't thnk that's going to work. So, throw some ideas at me and lets see if I can find this pesky little problem.

 

Could be several things.

Could be the coilpacks (again). When you replaced them, did you use OEM or aftermarket? Aftermarket coils don't work to well in our cars.

Could be tired/leaking injector(s).

Code 0201 is Ignition signal primary circuit fault
Code 0701 is Multiple cylinder misfire detected
These two codes are related!

I start with coilpacks (maybe the last two you haven't changed yet) because you state that the car runs great cold, but starts getting crappy when it warms up.

 

Would a leaking injector cause it to throw the code 21? If not, I'd lean more towards coil packs.

 

Yes, most definitely. When I had injector issues, I had the same two codes as you. The only difference is, my car ran like crap all the time, hot or cold.

 

Due to the age of our cars, this year we are seeing an increase in the number of leaking injector cases. The problem appears as uncontrollable flooding that makes engines hard to start. Misfires from one or two cylinders receiving too much fuel that results in flooding while running.

Cooked and clogged catalytic converters from too much unburned fuel that can also cause a hard to start issue because the engine cannot breathe properly. I personally experienced clogged cats that were caused by two leaking injectors.

Wiz - I think we should start a new thread named "The Failed Injector Thread" to describe the various issues, conditions, and cures where we can collect stories and pictures as an easy reference. Perhaps the thread could have a survey where we can track engine age, mileage, and any relevant information that may be used for predictive purposes.

 

All good info, thanks. Now, one last question before I decide how for to tear into this.

Since the car runs perfectly when cold, would you say the problem is more likely coils or injectors?

 

How do the plug look? Usually leaking injectors will leave a blackened or wet plug with fuel smell. The issue is uncontrolled fuel that results in flooding. Do you smell any unburned fuel from the exhaust one you get it started?