Fellas, I'm here hat in hand asking for help. Here's what happened: I was leaving work and started it up. It ran very rough and then died. I fired it up again and it was all I could do to get it home (limp mode?). I've done everything I know to do. Cleaned the sensors in the two intake ducts, and did the reset dance. I even changed the plugs (knowing that wasn't the problem). It will crank and run but it's rough as a cob and dies shortly. I have an OBD II code reader but it doesn't show anything. I think it was "born" on the cusp of the year so I'm including an image of the info on that. Any help would be greatly appreciated especially in light of the current (brutal) economy, I would have to take out a loan to get it fixed so I'm forced to DIY it. Thanks in advance. P.S. It runs like the older vehicles (350 Chevy) used to when the timing chain would "jump time".

 

So this just happened completely out of the blue yes? You drove to work, car ran fine, went to leave, car ran like crap?

Was it raining that day? Did you fill up fuel at a different gas station that day?

It's not throwing the check engine light when it is running?

Look up the specs on your OBD2 reader and make sure it handles protocol ISO 9141-2, that's what these car use. Basically it's the same language (OBD2) but there's a lot of different dialects (ISO 9141-2 in this case).

What happens when you unplug both MAF sensors then start the car. Does it idle smoothly?

If all those things check out I would do a spark check (first pull the fuel pump relay), pull all the plugs, then go through 1 cylinder at a time, plug in the coil pack, put a spark plug in the coil pack. Then with a gloved hand hold the spark plug tip 1/4" away from the intake manifold (hold it by the coil pack end so you don't get zapped) and have someone else crank the engine while you visually check spark an EVERY CYLINDER. If you don't have a second person you can use some rope like paracord to tie the plug into place where you can still see it while cranking the engine.

I'm fairly sure you'll find the issue, either a dead cylinder or a MAF sensor failure, or it's just suuuuuper low on gas and your gas gauge isn't functioning properly.

Has the car ever given you any other problems?

 

It ran fine until I went to turn into my parking space and it coughed and sputtered which I thought strange but you know, gotta get in to work. When shift was over, I got in to leave, it was sputtering and coughing and it was drizzling rain that day. Didnot fill up at a different place ( I'm OCD about going to the same places. I'm going to work on it tomorrow. Check engine was on for about 3 days (I tightened the gas cap, which usually does it). And no, it has never given me problems other than the loose gas cap thing and of course, the trans went out once at a cost of nearly 4K to put a used one back. I assumed ( I know, never assume) that OBDII was OBDII. I'll check the dialect and get one that speaks "Infiniti" as well as do the other things you suggested. I want you to know that I genuinely appreciate your help on this. Most people these days won't stop to help someone. I'll get back to you when I've done all the diagnostic tests you suggest. We're having a triple-digit heat index for the next couple of days. Thank you, sir.

 

Usually your local auto parts houses will scan the car for free and give you the codes, they want you to buy more parts from them so...

My gut suspicion is you had a cam or crank sensor fail though, that's usually the symptoms. However the rain can complicate things because the cowl drain is prone to clogging and then water pours on top of the IPDM (engine bay fuse box).

Since you had the CEL light on there are stored diagnostic trouble codes, just don't disconnect the battery before you get the car scanned or it will erase the codes.

If you do end up having a P0335 (crank sensor) or P0340, P0345, P1078, P1084 (cam sensors) then make sure to only replace them with Genuine Nissan OEM or Hitachi (the OEM manufacturer for those items). These cars are widely known to not play nice with any aftermarket sensors.

Here's a picture of the code layout for cam sensors, it's for the 2005-2007 coupe VQ35DE Rev-Up engine but it should all be the same for your VQ35HR 2007-2008 sedan engine. Just be aware that they don't have separate straight or angle head sensors, the HR uses all the same cam sensor for everything I think.

 

Well, I went to check it out today and the battery was dead (of course). I charged it up and put it on a load tester and it tested out bad. I put another battery in it ( not as easy as it should be) and fired it up (after it went through all the self-checks). same crap (of course) with the exception of a yellow dash light I hadn't seen before that said "SLIP" Aas near as I could tell. I'll have to research that online. I unplugged the MAF sensors and it would rev to about 2-3K (normal on start-up), then it would pulse. Up, down, up, down, so I shut it down. I checked out my OBD II reader and it is a CP9135 and not ISO 9141-2, so I'm in the market for another reader. I think I'll be able to work it out then. This is the part where an old man rants about the new stuff with unnecessary and unreliable sensors but I'll spare you that part. Instead, I'll say that you went the extra mile (with graphics too) to disclose esoteric information in order to help a stranger, and in my book, that makes you a damn decent human being. I appreciate you and I'll let you know how this thing ends.

 

It won't run to take to the Oreilly's for a scan, so I bought an OBD II code reader that has the protocol you mentioned. It said "no stored codes" which I suspected because of the dead battery. I had a code read before this happened and I don't remember what I did to make it go away but I did take a pic of it. It was P0507 "idle speed control system" Could this code cause this issue? When it first fires up, it runs great for a second and then falls off. You can keep it running for a short while by patting the gas, but it ain't pretty. I'm not one to just buy parts to throw at the problem but if you're fairly certain (I always trust *my* gut), I'll replace all those sensors. I hate to have it towed to a shop or worse, the dealer and the way things are right now that's out of the question anyway. I'll tell you what, the last two years have been so bad, nothing surprises me anymore. I appreciate the time you've already spent on this.
EDIT: I forgot about the spark check. I'll do that before I do anything else.

 

Unplug the MAF and see if it will run then.

 

Will do. There are two.

 

I fired her up today and went ahead and hooked up the OBD reader (though I knew it wouldn't run long enough to generate a code). Lo and behold, it ran! It didn't run well but it ran long enough to generate a code and come up to operating temperature. As a matter of fact, it ran until I shut it down. I shut it down because when the idle dropped off, it would pop inside the intake (backfire) Which (I believe) was because of the P0300 code (random multiple misfires) that it produced. When I took it up to 2-3K RPMs, it would smooth out. I pulled the right MAF sensor while running and it started surging up and down. I pulled the left MAF sensor and there was no change. I plugged them back in and still with the surging so I shut it down to "reset." I fired it back up and no surge. At this point, I think I need to check the spark again (just to be sure), and if it's not a coil pack then? I don't think it's coil packs because of the 'random' part of the code. I don't think more than one coil would go bad at a time. Your thoughts?

 

I went out again today and got it to run then shut it down and disconnected both MAF sensors. When I fired it up, it would pulse from 1500-2500, 1500-2500, 1500-2500 and so on. I cleaned the MAF sensors and repaired a crack just in front of the hose clamp on the intake hose from the breather box and inspected the other one. It was fine.

 

Well, I told you I'd let you know how this ended. I believe I'm getting close. I'm gonna take the intake off (it needs a valve cover gasket anyway) and I'll be able to access everything that could be a problem. On a side note, I know in my heart of hearts that if this were a good old carbureted Chevy, I would've been on the road a long time ago. They say that these new cars are designed to be "more efficient." Brother, if this is efficient, I'll kiss the *** of every member on this website. Breaking down on the interstate and finding a piece of wire to jump the coil and get you home. THAT'S efficiency. Not spending $75 so the engine knows how much air it's getting. That's a screw turn on the "obsolete" vehicles. I'll get off my soapbox now. I know I said it before but I really appreciate your help. I'm lost on the new stuff but it looks like I'm gonna have to learn. And now electric cars. Geeeesh.

 

Are you 100% sure there isn't a coil pack harness wire that got swapped?

 

Brother, these days we are living in, I ain't 100% sure about anything. I will say that it would be hard to do, the way they are laid out on the harness. Add that to the fact that I did them one at a time and I'll say that it would be highly unlikely. I tried to send a video but the file is too large. It was audio of it idling then it would surge, then level out for about 15 seconds then drop RPMs and idle rough, then pick up and smooth back out. I took the intake plenum off today as I have to change valve cover gaskets anyway. The gasket had some flat spots in it but didn't look like it had been leaking. I will be changing it though. An interesting thing happened when I turned the plenum over, dirty green fluid came out of what looked like a vacuum line connected to the throttle bodies. I have no clue about that. I'm gonna check the cam pos sensors and exhaust position sensors and depending on the price, may change them anyway. At this point, I'm thinking it could be an injector. possibly? Or maybe an ECU? Did I mention I hate the new crap? It's great before a hundred thousand though and it sure does look good sitting in the yard. -Bob

PS- My engine code is VQ35HR not DE

 

Those were coolant lines running to the throttle body.

Honestly at this point I think you should just take it down to Nissan/Infiniti for a 1 hour diagnostic. It will cost you 1 hour of labor for a diagnostic and there's a LOT they can do with the Consult-III dealership tool to quickly troubleshoot the issue.

 

Well, that's one of those things you can't afford NOT to do but in my case, I literally can't afford it in this current (brutal) economy. If I could, I would've done that to start with. Besides, I have it pulled apart now. SOMETHING will happen. Did I mention I hate this new $h17? I love my old Chevys. They're not as fast but they've never let me down. I gotta go put this $h17box back together and do some testing. Thanks again.