maxi-freak

Greetings,

My Maxima bucks like a bronco when accelerating - at around 1500 to 2000 RPM (but only when fully warmed up). I have replaced the spark plugs, distributor cap, rotor cap, fuel and air filters. The car runs like a champ when not warmed up. I have checked the codes on the ECCM and all modes indicate normal operation. I have also replaced any vacuum hoses that looked questionable. The car runs great at all times on the highway.

Any thoughts?
Thanks,
Jamie

CoolMax

iTrader: (7)

buck and surge when I'm hot!

Tranny problems?

Mike S.

Sounds like a bad coil. They act up when they get hot. You have one on your VG.

maxi-freak

The coil? This really seems to be fuel/air related. The only time that the car wiggs is in the lower RPM range (when hot, accelerating) but never in the upper RPMs. If the coil were the culprit, would it not fire low secondary voltage throughout the RPM range. I did check out the mass air flow meter and I have good battery supply voltage, and when idling the spec is 1 to 1.7 volts on (I forget which pin). I had .5 volts at idle which sounds suspicious to me.

Jamie

MadMaxBrent

I've had some idle / low RPM problems before and have found that the airflow meter is really sensitive to what it expects to receive. A K&N panel filter cause the meter to lose the plot and a standard filter with a split in it cause it to go spastic also. After replacing these filters with a OEM panel filter and resetting the ECU the problem was resolved.

Also look at the PCV valve and the throttle position sensor. These too can cause some grief.

Brent

maxi-freak

Yeah...I've replaced the PCV valve and adjusted the throttle position sensor. It has a new factory air filter as well.

I think that Mike S. is is on to something. I never would have imagine that my coil could be bad until I measured 12M ohms across the secondary windings! The primary was OK at 1.0 ohm. Also the coil to distributor wire was OPEN! Hard to believe that the thing was running at all. Anyways, I replaced the coil and ignition wires and will find out in the morning when I drive to work if the thing is repaired.

Will post with the results of these changes.....

Thanks for all the suggestions.
BTW- This black `90 SE has 250,000 miles on it and looks like it has 20,000. These cars are awesome. I have 2 of them.

Jamie

maxi-freak

OK...changing the coil and plug wires fixed the problem. The car drove great this morning on the way to work. From here on in - if I want any bucking, I'll go to the rodeo.

Jamie