M37 Intermittent Rough Idle and Throttle

Forum for Infiniti M37, M56 M35h Hybrid and Q70 owners.
Posts: 9
Joined: Sat Apr 17, 2021 9:44 am
Car: 2011 Infiniti M37x

M37 Intermittent Rough Idle and Throttle

Postby chillyjoyner » Wed Jul 07, 2021 8:24 pm

Hello, I have been scouring for information on this and haven't been able to find the problem with my idle and throttle.

I have a 2011 M37X,
I recently (3 months ago) changed my spark plugs (so you have more info). Everything has worked fine. If anything, the car was peppier.

As of a week ago, the engine will idle fine, then miss. Then idle fine, then miss. It only does it every once in a while, but it is noticeable.
At first, I thought it may be bad gas. But I burned the gas tank down to almost zero and refueled it. Still getting the same problem.

Also, It is not happening just at idle, as I am accelerating, say up a hill, sometimes I can feel that miss. However, I can nail the throttle and down not feel it at all.

Any ideas?

Posts: 19
Joined: Tue Jul 02, 2019 1:41 pm
Car: 2012 Infiniti M37x
2009 BMW X3
2006 BMW 330xi
1999 Mazda Miata MX-5
1990 Ford Taurus SHO
1973 Norton Commando 750
1972 Triumph Bonneville 750
Location: State College, PA

Re: M37 Intermittent Rough Idle and Throttle

Postby crrraaig » Thu Jul 08, 2021 3:39 pm

Maybe a bad coil? My '12 also has a *very* occasional miss... started noticing over a year ago (about 3k miles) and thought I would give it time to develop. It has not. Still very occasional, sometimes at idle, sometimes when I'm only just on the gas. Dealer was recommending MAF cleaning due to miles (70k) and I've seen it suggested in the forums, but passed on the service so far.

I do not think a passenger would notice the miss (the tech didn't either), it is really a single spark missing if it is a ignition miss. Really just a slight shudder or stumble to a otherwise smooth engine.

In other cars, I've been able to motivate a bad coil to act up by putting the car in as high a gear as possible heading up hill and lugging the engine... no luck with the M... so far :)

Are there specific ignition coils that tend to go bad on the 3.7? I know on some other engines (n52, 3.0 duratec) the ones up against the firewall tend to go first.

Been long enough that I'm getting concerned about plugging up my cats... thinking of just getting three coils and doing one side and then the other to see if I can find the culprit, but still not sure it's a coil thing!

Return to “Infiniti M37, M56, M35h Hybrid and Q70 Forum”