[jautry27]

I've taken the spark plugs out before, changed them, had the plastic part of the throttle body off before, cleaned it, and so on with no problems. Did it today the same way I always have. Only difference was that I actually unplugged the Electronic Throttle Control to wipe some of the gunk out when I cleaned it. Pulled the coolant lines and everything off.

Now when I start it, it revv's up to about 2,000 rpms and back down to about 1100 or so while it is in neutral or park. When it's in gear, it's not an issue.

Any ideas what it could be? I'm 99.999999% sure I put all the vacuum lines back on properly, but I read on a Honda forum where some of them said there could possibly be an air bubble in the coolant line going to the ETC.

Help please.....

 

[MuzzleNChains]

I suggest checking vacuum lines and also the air intake to make sure everything is tight with no leaks.

 

[jautry27]

I suggest checking vacuum lines and also the air intake to make sure everything is tight with no leaks.

I am going to go back through and make sure everything is tight and torqued down right. Worst case scenario, I can replace all the vacuum lines. It's possible I could have cracked one. The car is an '07 Versa S Hatchback with 180,000 miles.

 

[robj80]

Check the maf plug. If that checks out read through the fsm. I'm not sure about the versa but older nissans you need to perform an idle air control procedure when you unhook certain sensors.

 

[jautry27]

Check the maf plug. If that checks out read through the fsm. I'm not sure about the versa but older nissans you need to perform an idle air control procedure when you unhook certain sensors.

Did the Idle Air Control procedure to no avail. MAF plug is tight and cozy. Only other thing I can think of would be a vacuum leak. I'll just have to pull them off one by one and check

 

[jautry27]

Did the Idle Air Control procedure to no avail. MAF plug is tight and cozy. Only other thing I can think of would be a vacuum leak. I'll just have to pull them off one by one and check

No cracked vacuum lines either

 

[Shaun]

Versa; Idle; RPM's revs up and down

I know this thread is old but wanted to share my experience in case this can help anyone else out. 2007 Nissan Versa. Change spark plugs, put in ignition coils, and put new gasket on intake manifold. While I was at it, I've decided to clean the throttle body. I open the flap can clean inside really nice. Later I found out that I was not supposed to open the flap. Oops. Got everything put back together and the engine would not start at all. Tore my hair out for two days trying to diagnose. On a whim, I decided to buy more spark plugs and install them. Car fired right up.
These were defective
Autolite XP5684-4PK Iridium XP

These worked perfectly. Denso Spark Plug Iridium TT

Then a new problem. At idle engine would rev up and down, up and down. 2,000 to 3,000 rpms. Check the fault codes with an ODBII scanner and an app called Torque I got on my smartphone. Fault code read P0102 which is Mass air flow sensor circuit low input. So I took out the sensor and sprayed it with Mass airflow cleaner. Let it dry and put it back in. I reset the fault code and started the car back up. P01102 code went away and got a new code. P0507 which is Idle air control - RPM higher than expected. Still at idle car revs up and down continuously. I read that a clogged PCV valve could be the culprit. Bought a new one and installed. Still revs up and down. Could be anything from a vacuum leak to throttle body to Mass air flow, etc. I sprayed starter fluid around manifold and hoses to try and detect a leak. Nothing came up. I also did the relearn procedure for the Accelerator pedal, throttle valve and Idle air volume learning about 20 times. Still at idle rpms revs up and down. Browsing the internet I read that somebody said it could be a faulty ignition coil. They were all new, but what the hell. I installed the old ones, except for the one I knew was damaged. I also over tightened the intake manifold bolts and throttle body bolds beyond specs. I thought maybe there could be a slight leak. Viola, car started and began to idle normally to 650 to 700 rpms.

Intake Manifold torque specs are 20 ft lbs. I tighten to 25ft lbs *Foot pounds.
Throttle body torque specs are 89 in lbs. I tighten them to 100-inch lbs. *Inch pounds.

So changing the ignition coils or over tightening the bolts fix the idle fluctuation? I'm not sure but, it's fixed.

 

[amc49]

'...RPM higher than expected.'

A sign the engine cannot control the idle, too much air getting to it. Where the rpm comes from, too much air for the ECM to control back within range. How faulty thinking that a clogged PCV valve can do that I don't know.......impossible. You gotta think, clogged is LESS air. Coils can only LOWER idle by being defective, you gotta think again.

If you reused the TB base gasket likely that, I saw lots of people do that and then the problems begin. They think the gaskets reseal but they don't. The modern methods of sealing used commonly don't get better with overtightening, the best way to break the commonly plastic parts used there now, Luck there, it usually doesn't happen.

The previous plugs likely had nothing wrong with them, the closing back up of the 'flap' likely closed down 100% but there is a small aircrack there and it took a bit of time for the ECM to re-initialize to crack again, until then the engine WON'T start as there is no air getting to it.

'These plugs are defective' is one of the silliest things I heard while I was in parts...........no insult intended at all there but it is what it is. Almost impossible for a plug to be defective if it is not visibly broken or errored in some other way

 

[schimmerb]

I'm sorry but your English is difficult to understand. I've had the same revving problem since I changed my plug. I mention that only because of what you have to pull off the engine to get to them. (What a stupid design. Our old Sebring plugs were right on top. Nothing to remove.) I'll have to go through the whole thing when it's a little warmer so I can check the vac lines and cracks in the manifold.
Would this also cause poor (30MPG) mileage?

 

[amc49]

Look at the work done there, difficult or easy, when you take it on yourself you are saying you are good enough to get the work done right.

Like with other things on cars, they are making it harder now to force people to quit doing it themselves and take car back to the dealer.

Fed up yet? It will only get worse. On many cars now you can't even change the battery without taking it to the dealer now to update the computer system based on a new battery.

 

[Chaz]

'...RPM higher than expected.'

A sign the engine cannot control the idle, too much air getting to it. Where the rpm comes from, too much air for the ECM to control back within range. How faulty thinking that a clogged PCV valve can do that I don't know.......impossible. You gotta think, clogged is LESS air. Coils can only LOWER idle by being defective, you gotta think again.

If you reused the TB base gasket likely that, I saw lots of people do that and then the problems begin. They think the gaskets reseal but they don't. The modern methods of sealing used commonly don't get better with overtightening, the best way to break the commonly plastic parts used there now, Luck there, it usually doesn't happen.

The previous plugs likely had nothing wrong with them, the closing back up of the 'flap' likely closed down 100% but there is a small aircrack there and it took a bit of time for the ECM to re-initialize to crack again, until then the engine WON'T start as there is no air getting to it.

'These plugs are defective' is one of the silliest things I heard while I was in parts...........no insult intended at all there but it is what it is. Almost impossible for a plug to be defective if it is not visibly broken or errored in some other way

 

[tutti57]

Buy yourself a scantool with live data for around $15 to see what is going on. Watch some videos on fuel trims. If they are high at idle and get closer to zero if you hold about 2500 rpms, then you have a vacuum leak. If they are normal then you want to make sure your air filter is fully seated in the box and do all of the throttle body learning procedures.

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