Engine Troubles

[Toyota Vienta]

Hello Everybody firstly id like to say well done with the web site not alot or camry enthusiasts down in Aus compared . I am new to this forum so bear with me . I have already tryed to use the search function it seems no one else has my problem or i am using wrong terms.

I drive a 99 Toyota Vienta Vxi which is bassicly a camry equivalent to your Gen 4 1mzfe,
it has about 190,000 kms on the clock so its getting old. No modifications done to the engine except connecting the wire to the battery for an amp. The Problem is when im driving for about 30 mins the rev counter just goes up and down like its stuttering or as if someones giving it a bit of trhottle every say half second. Mind you this doesent happen evey time its a every now and then thing . When at a halt idling it stays the same even when i change into park, neutral ,reverse ,position . The revs only range from say about 900 to 1800 going up and down. I have been to my local toyota delear service center twice and they cant seem to find the problem. The only way to temporarily fix it is to turn the car off for an hour and its back to normal. Or just floor it and it goes away. Its recently been serviced also with oil/fuel/engine filters replced and injectors cleaned. Im just worried if this is damaging the car.

Much Aprecciated
JEFF

[bronzemaxell]

your rpm needle fluctuating at idle speed?
have you clean your throttle body or pcv?

[Toyota Vienta]

Yes the needle is flucutuating so is the engine as i can feel it , not only at idle but also at a cruising speed. I also forgot to mention on the last service they did have the throttle bodys cleaned well i get someone to also to that. What is a pcv?

Thanks very much any other suggestions?

[trypsix]

Question: What is the purpose of the PCV valve and what are the symptoms when it goes bad?

Answer: PCV means positive crankcase ventilation. This valve uses vacuum from the intake manifold to draw the fumes from the crankcase. Symptoms of a faulty PCV valve are poor idle and excessive pressure in the crankcase.

(from some webpage or another)

I found 1 where the intake manifold connects to the rest of the engine on the passenger side. There are two maybe? I dunno.