Intermittent Check Engine - Rough idle

[dbaxRonin]

So a while back my check engine light came on, but the car ran fine. I figured it was just an O2 sensor and had planned on taking it in to check the codes. Last week, the light went away.

This past weekend I visited my folks and the car sat for a couple of days. I got in on Sunday to head home and noticed the engine was idling pretty rough. It got worse when I put it in Drive with my foot still on the brake. Once I got up to the end of the driveway, the engine light blinked at me 4 or 5 times then went away, but it still ran rough. This happened again when I turned to get on the freeway onramp. After that for the remainder of my 125 mile trip, it ran fine and no engine light.

Today, it ran fine going to work, then fine again coming home for lunch and returning to work. After work, it still ran fine. I stopped at the gas station for some provisions, and when I got in and started it up, the rough idle returned and the engine light came on.

I plan of course to take it in and get it checked out, but just curious if anyone has any quick ideas what my problem could be. TYIA

[tigersharkdude]

IMHO Im gonna say its a coil pack. Take it to Autzone, advance, etc, etc. If the CEL has been on recently the code should be stored

Blinking CEL usually means misfire, and coil packs are normally the problem

[dbaxRonin]

Thanks for the input tiger. That sounds like a definite possibility based on how the engine runs when the problem occurs. I am going in to have the codes checked tomorrow morning so we shall see what the diagnose is.

[tigersharkdude]

In for what you find out

[NutriaforBreakfast]

Your mass air flow sensor might be starting to go out (or is really dirty)

[dbaxRonin]

It was indeed a coil pack. #2 was on the fritz. New pack and a new set of plugs and so far so good. Hopefully that is the end of it. Guy at the shop warned me though that in his experience, once one goes, the rest aren't far behind.

Can anyone recommend a good place to buy the packs from for a decent price? I can probably replace the rest on my own and save a few bucks.

[loystock]

I buy my parts from IoS (Infiniti of Scottsdale, a.k.a. "infinitipartsUSA.com, everythinginfiniti.com, everythingnissan.com. At 25% off MSRP and no tax if outside AZ, their price is very hard to beat. I just spent@ $600 from them for my Bi-Annual Maintenance. Joe Tesensky and staff are knowledgeable about Infiniti/Nissan cars. Each coil pack for your car is $80.25.

http://www.infinitipartsusa.com/partloc ... atalogid=0

[tigersharkdude]

I buy all of my packs at Advance or Orieleys. Opt for the BWD intermotor brand. I have 4 of them, and no problems.

[ERUOTANEN]

I had the same symptoms with my '94 Maxima. Intermittent problem, very irritating. The only error code I got was low fuel pressure. That was not the problem. Mechanic said it "could" be mass flow sensor/transmitter but that does not show up as an error code. He had another customer with the same problem, and when he replaced mass flow sensor, it went away. He would not put one in unless I requested it, because he did not want to sell me something he could not prove was bad. I told him to go ahead and do it, and that fixed the problem.

[loystock]

MAF sensor problem may not necessarily throw a fault code. And unless you have an oscilloscope, voltage readings are not really helpful. First thing to do is thoroughly clean the MAF sensor (with zero-residue contact cleaner or CRC MAF Sensor cleaner). You can also disconnect the MAF sensor (will generate a P0100 code which can be cleared), start the engine and check if engine hesitation/surge goes away. But please, do not drive with MAF sensor disconnected as your car will be in 'limp mode' (injectors firing simultaneously and RPM limited to <3000)