Noticeable when in drive at a stop and when accelerating. Sometimes feel like it's going to shut itself off.

The q45 has this issue when I first got it, now the Maxima is doing the same. Had to drive the Max 1,000 miles last week. At one point, going uphill and accelerating caused the check engine light started blinking...turning the heater all the way made it stop, as I felt it was going to get too hot.

So I'm wondering if this is the spark plug boots perhaps or the spark plugs themselves? Seems like a similiar issue a Camry I had was doing, and the plug wires being changed fixed it. I did have a bad valve cover leak that was fixed earlier this year.

About spark plugs: does anyone take the time to gap them, or just put them in straight out the box? Assuming you're using Denso or NGK brand specific for the vehicle.

 

First of all, the blinking cel and the need to turn the heat on to get it to stop begs the obvious question.
Was the the temp guage also pegged at hot?

Don' bother with the rest till we know the rest of the story. What had been happening during the week before this happened? Overheating, cold interior heater?

Your cooling system was under stress up the hill as the problem happend. Seems like you have cooling issues.

Now we need to know if the engine is ok. Are you losing coolant, but not seeing leaks?

Hold off on buying plugs or coils. I want to see photos of the plugs. Also information about which cylinder they live in.

You dont want to see oily electodes. Should be dry and tanniish . White would mean steam cleaned ones.

 

Ok...on the q45 I've not yet disagnosed it. Codes say multiple misfires.

The Max just started doing this out of nowhere during a long trip. No overheating, however....I'm suspecting a leaking water pump as I'm seeing white ashy studf come and go on the power steering belt and now the alternator. However....just today, I was at a light at night and the gauge starting going up and had to turn the heat full blast. I have a car bar on with a grill mesh, that's coming off because it tends to make it run hot if the cooling system is not to par.

NOW: I've had gauge going up issues before. Usually it's those thermostats not opening fully after a few thousand miles. Sometimes a fan motor. But I've replaced fan motors and thermostat is only about....well 2 or 3 years old now lol.

I even filled up with 93 gas as it seems to have stopped it, but then it comes back at random. I've also used 85 and 87 many times before and hadn't had this issue until now.

 

Your symptoms match a bad water pump.

the car is less likely to knock under load in high temp conditions with premium

By the way, our cars perform best with premium,
as mentioned in the owners manual.