Throttle problem!!

[ramzisleiman]

My 2003 2doors G35 recently had this annoying problem in the throttle! As im cruising, suddenly the revs cant go over 1200 rpm's and the slip, brake, and check engine lights show up!.. no matter how much i press the pedal.. the car just wont move! I tried another ECU, and changed the throttle sensors as a mechanic recommended, but none turned out to be the solution! anyone had this prob before or can help ?

[maxnix]

Have you checked the battery and alternator under load, not just superficial voltage output?

[ramzisleiman]

sorry! but i didnt understand what u said bout the battery and the alternator !? and how is it related to my problem.. and how can it be fixed! thanks!

[Q451990]

He is asking if the battery and alternator have been tested under a load - to make sure they are functioning properly. Batteries and alternators can appear to be working fine at idle with everything off, but then not put out the specified voltage under a load. In a car with so many electronic-based systems, low voltage can cause all kinds of quirky issues.

You mentioned that your "check engine" light comes on when this happens... there should be a code stored in your ECU. Did your mechanic check this code, and did he tell you what it was?

I know some of the G35s have throttle body issues... they are all drive-by-wire (not cable driven) but typically fail closed.

Heath

[ramzisleiman]

Well never tried to test the alternator yet!.. but i did say the check engine light goes on! but when things go back to normal, the check engine light turns off by itself! and everything is normal! and sometimes i turn the car off and turn it on the next day and the problem is still the same!.. and sometimes, i just switch it on and off several times, and things go back to normal, you guys still think it might be the alternator?.. i mean shouldnt it be normal the next morning no matter what load was on it at the previous night?

[qship96]

take the car to your local dealer for a diagnosis of the problem.Much faster and cheaper than guessing if one doesnt have a good understanding of automotive concepts and mechanicals.

[Q451990]

Not sure how many dealers are local in Beirut - assuming we're talking about Lebanon and not a town by the same name in Kansas or something?

After reading this again, I think the throttle body issue may be what's being described.

In terms of the code - even though the light goes off, the ECU should store it for a while.

You might try posting in the G35 forums... a member named "SteveTheTech" monitors that area pretty closely, and seems to have a great deal of G35 specific experience.

Heath

[SteveTheTech]

It definitely sounds like a throttle body. The sensors are sealed into the unit and are not replaceable separately and I do not know how that was done I think it may have been a replaced throttle chamber without performing an idle volume learn and self learning. If the ECM detects an open circuit in the TPS or TM control failure it will set a CEL, as well as the Slip and VDC lights.

[maxnix]

Not sure how many dealers are local in Beirut - assuming we're talking about Lebanon and not a town by the same name in Kansas or something?

We'll never know unless he completes his profile.

[fixer]

we've had lots of problems with throttle bodys, the electronic actuator takes a dump and usually will turn on the slip and vdc lights on first before the ses light. you will need to reset idle air volume learn after replacing. I would recommend taking it to a dealer for repairs