When traveling to/from work in stop and go traffic. When traffic is moving about 25-30mph and traffic picks up I have to press the accelerator quite alot more than I used to, to get the car to move with traffic. Any ideas what is causing this? FYI I have 105k miles on the car. JWT pop and Cattman y-pipe.

 

The first thing i would look at is the throttle linkage. Is the cable tight? Mine was loose and i only have 35k miles. I tighten mine and the responce is great!

If that doesnt work, hav eyou dont a tune-up lately? platinum plugs (only), fuel filter, dirty injectors, or just plain old wear and tear.

 

Engine problems ...
- "Tired" Oxygen Sensors
- Clogged Catalytic Converter
- Obstructed exhaust system
- Clogged air cleaner filter
- Loss of compression (leaky valves, worn piston rings)

Transmission problems ...
- Failure to downshift as appropriate

Brake problems ...
- Dragging brakes (sticking calipers)

 

Daniel,

The pop is clean. I had the brakes done on the car and the problem was there before the brake were done. You mentioned trans failure to downshift as appropriate. What is appropriate. Also How do I tell/test for a clogged catalytic converter and an cbstructed exhaust system?

Thanks
Chris

 

The simplest and best way to evaluate your transmission's behavior is to take a test drive in a similar Maxima. Perhaps you have a friend or neighbor who owns a 4Gen Max. Compare with another Maxima and you will know right away "by feel" if your tranny is not downshifting as it should.

To test for an obstructed exhaust system make a manifold vacuum test as shown in the Haynes repair manual on page 2C-8. Normal vacuum at engine idle is 17-22 in-Hg. Snap the throttle open, let the engine rev to about 2,500 rpm, and let the throttle close. Snapping the throttle open should cause the vacuum to drop to zero. Snapping it closed should cause it to abruptly juump higher than the idle vacuum figure, and then return to that reading. A long delay in returning to the normal idle vacuum indicates a restricted exhaust system. This may be confirmed by temporarily disconnecting the exhaust system just upstream of the suspected blockage and repeating the test.

To test for a plugged Catalytic Converter, drill a small hole in the exhaust pipe just upstream of the Cat. Screw in a temporary hose fitting attach a long rubber hose a 0 to 10 pound pressure gauge. With the gauge inside the car, drive up a hill or accelerate and read the pressure. Normal is 1 to 2 pounds, restricted 3 pounds or higher. The drawback to this method is the small hole which will have to be sealed after the test. This may be done with a thick short sheetmetal screw or a small "blob" from a welder.

 

Daniel,

Thanks for the info I will do the vacuum test this weekend. As for the trans, the only others that I know with Maximas have Don VB so I can't compare (since I don't have the vb. Any other way to tell?

Thanks
Chris

 

I think a comparison with a VB mod car will still be valid as regards the transmission's willingness to downshift.

Take your Maxima to a transmission specialty shop. Tell them you are uncertain about your transmission's shifting characteristics. Ask for a no-cost road test evaluation.

You might also verify correct operation of the Throttle Position Sensor. For further information see the Chilton repair manual (page 4-18) or the Haynes repair manual (page 6-8).