Prado engine rev problem

Submitted: Tuesday, Aug 05, 2003 at 07:08

ThreadID: 6372 Views:8546 Replies:7 FollowUps:2

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Jason (macca)

I am currently experiencing a problem with my 2000 Prado 3.4 petrol.
In the past few weeks I have noticed that the engine revs fluctuate
between 900rpm and 1300rpm when at idle. The car is sitting there at
idle (900rpm) and then all of a sudden the car revs climb to 1300rpm
for no reason. I have also noticed that at times when I depress the clutch to change gears, the revs initially climb a few hundred rpm.

Any idea's......I took it back to those wonderful Technicians as there
now called at Toyota and they checked it with the "computer" and
because the computer said all is ok, they sent me on my merry way!!!!
I could not believe this joker at Toyota. He stood there and agreed that there was a problem with the car, but because the computer said all is ok, he refused to investigate the matter.

Thanks
Jason

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Reply By: paul - Tuesday, Aug 05, 2003 at 09:33

Tuesday, Aug 05, 2003 at 09:33

no idea and am keen to know the answer if i ever have that problem with my 2000 90 series. Try this site and post back the answer if you get one - http://autos.groups.yahoo.com/group/90scool/

AnswerID: 26824

Reply By: Member - Geoff - Tuesday, Aug 05, 2003 at 09:44

Tuesday, Aug 05, 2003 at 09:44

Jason,
Try using some carby & Throttle Body cleaner, be careful not to soak the spindle bushes to much as this stuff will attack them and make them stiff.Follow the instructions on the can.
If it is the problem that you have a build up of carbon around the butterfly the engine should idle at lower revs than before.
Some EFI systems dont like too high an idle speed and try to correct it subsequently the engine hunts like yours.
Try and keep the idle speed on the low side.
As a thought, make sure that there are no input signals from your cruise control,all the switches turned off.
Hope this will help I'm not a Toygota Technissshn.
Cheers Geoff

AnswerID: 26825

Reply By: Truckster (Vic) - Tuesday, Aug 05, 2003 at 09:50

Tuesday, Aug 05, 2003 at 09:50

Sounds like an air leak of some kind.

Take it to an independant mechanic and then back to Yota.,

Other thing is a letter to Yota head orriface would be a good idea, stating the spanner fool says there are problems but the computer doesnt...
Technology.. wonderful aintit

AnswerID: 26826

Follow Up By: Jason (macca) - Wednesday, Aug 06, 2003 at 06:32

Wednesday, Aug 06, 2003 at 06:32

I am going to see a local 4 x 4 service centre. Over the phone
he thinks it could be an O2 sensor playing up.

I rang Toyota customer service and told them my story, as
i expected, head office are on the side of the wrench monkey's.

FollowupID: 18432

Reply By: Truckster (Vic) - Tuesday, Aug 05, 2003 at 09:50

Tuesday, Aug 05, 2003 at 09:50

AnswerID: 26827

Reply By: tristjo - Tuesday, Aug 05, 2003 at 20:35

Tuesday, Aug 05, 2003 at 20:35

Guy's,

Could it be anything to do with the compensation for the a/c compresor??? Just a thought.

Tristjo.

AnswerID: 26870

Reply By: yarda - Wednesday, Aug 06, 2003 at 12:37

Wednesday, Aug 06, 2003 at 12:37

Jason, sounds like a sticking / blocked idle air control valve , the valve can clog with carbon and grime making the ecu hunt around to find the correct idle speed.
A dirty throttle body butterfly can also contribute to a rough idle, but the air bypass is often the problem ( it controls the air compensation due to temperatue changes / altitude etc) Cleaning both items is a fairly straight forward job if you are handy on the tools, the computer sometimes takes a couple of start cycles to reset with the re-installed and cleaned idle valve. If there is still a problem following this, grab your can of carb cleaner spray or aerostart spray and with the engine running spray around all of the inlet manifold gaskets, if there is a vacuum leak you will notice the idle pick up and stabilise straight away. This is a common problem on a lot of injected cars and causes the computer to hunt around constantly to rectify the manifold pressure signal and idle speed. If you find a leaking manifold, and initially took it to toyota while under warranty you should be able to get it fixed for nicks. Let us know how you go - Brad

AnswerID: 26928

Follow Up By: Jason (macca) - Thursday, Aug 07, 2003 at 08:19

Thursday, Aug 07, 2003 at 08:19

Brad

Thanks for the info. I really appreciate your reply. Do you have
an email address so i can send you an email regarding more info on this topic.

Jason

FollowupID: 18535