superdesi

I have a automatic 91 SE with 107K miles on it.

Recently, whenever I put the car in any gear to idle (except neutral) the car's drops to exactly 600 RPM and the steering wheel vibrates excessively. This happens when I have the car under no load (no headlights, heater, radio) as well as when I have the car under load. However, when I put the car in neutral, the RPM floats between 700 and 800 and the car stops the excessive vibration.

This happens when the car is in gear and idling (like at a stoplight).

Has anyone experienced this phenomenon?

BTW, the car runs fine and shifts fine.

RacerChoi

have you tuned your car recently?? check ur timing chain adjustment. Or if worse comes to worst, UR Flow meter may be messing up...

Foo90SE

I have the EXACT same problem with mine iv been trying to trace down WTH is going on with it since i got the car. I think its my 02 sensor. If that dosnt fix it i duno what it is
My car has had ALL maintence done to it...complete tunup(fuel filter/plugs/wires/cap/rotor/timing belt/oilchange)
although if the 02 sensor dosnt fix the viberation then im going to have to check my timing belt tension cuz im not 100% sure its right. If you havnt replaced the timing belt superdesi its time to do it and that is more of a saftey measure than anything

brubenstein

There is an idle speed adjustment. If this doesn't have any effect, then there is a good possibility that some some of the small air passages in the throttle body are blocked, or dirty. I would start by spraying injector/carb cleaner on, and around the throttle plate area. Do this without the engine running.

Foo90SE

hmm u reffering to the actual thing to adjust where the throttle plates stop or is there another way to adjust idle speed?

superdesi

I changed my timing belt around 500 miles ago. However, as far as tune-up goes..... I have only replaced the fuel filter and the air filter.

As soon as the weather warms up.....I want to do the spark plugs and the wire set as well as the PCV valve.

But can idling problem be because of a need for tune-up. When I am driving around the city or highway...the car doesnt vibrate at all.

Thanks.

Foo90SE

Did your car viberate before replacing the timing belt? i think mine didnt start till i replaced mine and im thinking i may of not got it tensioned right.

superdesi

Maybe ur right. But before I go back to my mechanic, I think I will replace the spark plugs and wires. Then, I will let you know what I find.

NYC GS4

iTrader: (2)

I have the same exact problems and I'm almost 100% sure thats its the motor mounts. My front is shot and rear is on its way. The 02 sensor for you will probably be a quick $110 down the drain unless your suffering bad MPG. BTW, this was backed up by a Nissan service diagnostic. Basically someone did me a favor and just checked the car out completely( Took the mech an hour, charged $70), I slipped the service advisor a $20 and walked out. They found exhaust manifold leaks on both sides, backed up by Midas and another Nissan dealer and now fixed. They also found that the mounts needed replacing and really didnt mention anything else at all.

superdesi

Would the motor mounts also cause the motor's RPM to 600 when under any gear (Forward or Reverse)?

Was your car an automatic or a stick shift?

I can understand the motor mounts giving the steering wheel a shake.........but why would they send the RPM to 600?

Foo90SE

well when u put the car in gear it goes under load then..thats why the rpm's drop. even tho you're not going anywhere the torque converter is putting load on the engine.

superdesi

I understand that fully.

But what is the correlation between the motor mounts and the dip in idle speed???

Foo90SE

nothing the dip in idle speed is caused by the trans...the viberation, if from a bad motor mount, comes from the wrong parts of the mount rubbing together when the motor is put under load

Strrrive

When that happened to me It turned out I needed to replace all of my mounts including my tranny mounts.

superdesi

About one week ago, I put six new NGK BKR6E-11 spark plugs.
I also replaced the pcv valve with a Purolator one. I replaced the fuel filter and air filter with Purolator brands.

I still have idle problem and the car feels and runs exactly the way it did before the tune-up.

BTW, the old spark plugs were pretty used up and old. So, I was happy putting in new ones.

I was expecting some improvement, but nothing really happened to put a smile on my face.

Maybe I should also replace the spark plug wire set.



[Edited by superdesi on 01-05-2001 at 11:19 PM]

Foo90SE

Well so far i have replaced--plugs,wires, dist cap, rotor button, fuel filter, 02 sensor and my car still vibrates just as bad if not worse now..so i guess i havnt even effected the system that is causing it.
I think mine is bearing clearances or timing belt too loose...