98 Infiniti QX4 started "bucking" this am

[West Coast Guy]

Wifey's daily driver started "bucking" this am. Purrs like a kitten in park, 6K 7K RPM smooth as a kitten. At low idle may seem a bit sputtery and inconsistent. Under load though, she has a real issue; starts to "buck" up around 2K RPM or 45 MPH. Also going up hill "bucking" starts at 30 MPH. Drove home with the flashers on and limped into the driveway. Any thoughts (other than taking it to a mechanic, which I may have to do)? TIA

[hospitalbuilder]

I may have had something similar. My 99Q started surging (what I called it), where the engine would rev up to about 2,500 rpm, cut out and die down then quickly rev up again over and over. If I stopped and turned it off and let it rest for 30 seconds or a minute, it went away when I cranked it again. Happened to me driving up to the Eisenhower Tunnel @ 12,000 feet. Needless to say sitting on the side of I-70 waiting for my car to get back to normal was not my idea of fun. I did two things, one or both of which have fixed my problem for a few months now. I cleaned the MAF and changed the fuel filter. I also replaced the air filter, but I do not think that was it. I cannot say which one made the difference since I did them both at once, but problem solved, so I really did not care.

Fortunately all of that is an easy DIY job, but be prepared to wrestle with the fuel filter. Good luck.

[West Coast Guy]

I got the shop manual and the fuel filter seems straightforward. What is a MAF and how is it cleaned?Thanks

[West Coast Guy]

I did a MAF search and found some basic details. Please enlighten me on how you cleaned yours.Thanks

[West Coast Guy]

I got it. Just towards the block right next to and in line with the air filter. Disconnect the modular electrical connection and remove two screws on top of the square module, lift the top off and there you are the MAF! Two wires inside look a bit skanky. I'll let you know how things work out.Thanks

[hospitalbuilder]

Sounds like you got it. But, I took off the entire MAF assembly, short piece of tubing attached to the air filter housing. I liberally sprayed the sensor inside the tubing with MAF cleaner I got from Pep Boys. Let it dry for 30 minutes and put it back in. I have heard that you are better off not to remove the actual sensor from the tubing as it is easily damaged.