Jack Rabbit trottle starts on a 1998 QX4 with 158K miles

[Merlot66]

A gal pal has a 1998 QX4 with 158K miles...nice shape always maintained. Unfortunately I noticed that when you accelerate from a stop no matter how lightly you press the accelerator pedal, every one in the vehicle ends up having their head snapped back. Otherwise it runs fine. Timing belt and water pump have been done. Get the "normal" mileage {actually 19 on the Hwy with some TLC}. I did the plugs, wires and air filter. I even lubed the accelerator pedal and linkages under the hood. Only seems to help for a day or so...then the same results. Frustrating! I drive a 1989 300E Benz with 360K miles on it...and I know how to accelerate smoothly. Possible CHIP problem? Any thoughts out there?

[03Chillinkoot]

Just needs a simple throttle body cleaning. And welcome to Nico.

[Merlot66]

Thanks for the welcome!

Man-oh -man what did we do without the Internet 35 years ago when I owned a Suzuki X-6 Motorcycle that needed replacement crankcase seals?

Do you mean a decent cleaning on the exterior of the throttle box (as in a good dunking with a clean agent) or does this need to be "opened up" if that's possible? I assume you mean the former?

[KoukiS14]

Like to also welcome you to NICO!I'd add to this but I shouldn't be on here at work anyway...

[Merlot66]

03Chillinkoot... I am in Toronto currently at 416-561-9466. Can we talk?

[Merlot66]

OK then...is a "Throttle Cleaner" product available in an aerosol can? Let me guess?..... take the Air Cleaner housing off...... have direct access to the throttle opening and assembly and....... spray the "cleaner" into the "throttle/plunger opening" while the engine is running.

Hmmm?

Am I close? Is so...what product should I buy? Any thoughts/recommendations?

If not.....please ... "all knowing one"....what should I do next???

Kindest Regards,

Merlot66

[Merlot66]

OK... with the help of Google I have found numerous articles posted on "Throttle Body" cleaning...including some on Nissan products, I figured it out. Next time I'm in Nashville I'll get my hands dirty. Thanks again to everyone for all your "hep" as they say in the South.

[fueler]

Merlot, I don't know if a dirty throttle body could be causing "surging" and jackrabbit-like behavior. Because the crankcase ventilation is connected to the black plastic intake tube (for smog legal purposes) our throttle bodies normally get dirty and gunked up with oil (oil vapors from the crankcase ventilation). The symptoms of a dirty throttle body is gas pedal not easy to move, or throttle reponse reacts slowly... and throttle not closing even when you let off the gas pedal.

It is easy to pop off the plastic intake tube (where it is connected to the large metal throttle bode and intake manifold) When you take it off, you will see the butterfly valve that can be cleaned with throttle body cleaner, available in aerosol cans at any auto parts place. Another possibility is a dirty MAF sensor... would cause poor acceleration, slight surging, and horrible gas mileage. The MAF sensor is in the intake tube and can be (carefully) cleaned with electrical parts cleaner, also in a aerosol can. Do not drop the MAF sensor or touch the little metal part with your fingers - it is easy to break and expensive to buy. Good luck, let us know what you find.

[Merlot66]

Thanks! I appreciate your in site. Will do both as you suggested. The MAF sensor will be handled with care. Will let you know what I find!

THX ....BIG TIME!

[fueler]

Also found this: http://www.nicoclub.com/truck-....html (change the nicoclub to nissanforums, stupid filter wont let me post the correct link) I think you're going to have to do some troubleshooting...

[Merlot66]

Finally back down in Nashville this past two weeks. Did the Throttle body cleaning with a clean shop rag, tooth brush and Canadian Tire Throttle Body Aerosol (imported from my drive from Toronto and my local Canuck Tire Shop) as well as gentle cleaning of the MAF. Results were good! No more Jack Rabbit starts... although the starting idle jumped up to about 1000 rpm. Seems to calm down to about 850 after the engine warms up. Could be a throttle cable "idle adjustment" required... (any thoughts out there????). The trottle body didn't look that dirty for 158K miles...but the whole procedure seem to help BIG TIME! SO thanks again to those Gurus who contributed to my enquiry.

Cheers

[fueler]

Great! It's normal to idle over 1000 rpm on a cold start.... just your fast idle valve operating as it should.... once the engine warms up slightly, it should drop to under 1000...

[Andrew502]

Don't forget to unplug the battery and let the ECU reset. This will allow the car to relearn it's idle much faster. Otherwise, you will end up with the higher idle +1000, for a bit.

Use CRC (CNC?) Throttle Body Cleaner and MAF Cleaner. The throttle cleaner is teflon friendly and the MAF cleaner is plastic friendly. Don't use any metal or paper towels when cleaning the butterfly valve or throttle, just a few shop cloths.

You will also want to put a shop cloth under the open throttle to prevent that stuff from dripping on the brake fluid container or headers.

You can use a small allen wrench to hold the butterfly valve open, by propping it next to the cable that actuates the valve (on the outside of the valve).

Try to wipe out as much cleaner as possible, so you don't push gunk into your valves and you won't have to burn as much cleaner. That's what the white smoke is from. Sometimes the car will hesitate to start the first time after this treatment.

I wouldn't recommend removing the entire throttle body assembly. If you're gonna do that, then remove the intake manifold and clean it too.

This will smooth your idle, regain low end torque and make you feel better.

But to be honest, 1st gear is just plain snappy. This car holds most of its torque power in the low end. You could always start it in 2nd if it lets you.

[chillinrick]

do you think that cleaning the throttle body in a 1999 version of the same model (QX4)(with only 65000 mi on it) would get it back to normal? the problem is that some times after stops such as lights or signs, the cars accelerator will be stiff and as a result you must pull off a "jack rabbit" to get it going.
Modified by chillinrick at 1:09 PM 1/23/2008

[fueler]

do you think that cleaning the throttle body in a 1999 version of the same model (QX4)(with only 65000 mi on it) would get it back to normal? the problem is that some times after stops such as lights or signs, the cars accelerator will be stiff and as a result you must pull off a "jack rabbit" to get it going.

Modified by chillinrick at 1:09 PM 1/23/2008

That sounds like exactly what you need, throttle body cleaning

[chillinrick]

thanks Alot!!!