[jamezckf]

When I start my engine, the rpm on the dashboard always fall under approximately 700rpm, and the engine shakes really badly. I have to apply some gas to raise the RPM in "P" gear to fix this problem every single time.

Any cause to this problem? I tried flushing the engine, replacing spark plugs, spark plugs wire, cleaning air filter, and even replacing a worn out battery... :?

The only conclusion I could think of is that my engine is getting old and worn out, its a 1999 year Rav4 with 113000 miles.

Please help, any suggestions would be greatly appreciated

 

[Bogatyr]

jamezckf,
113k miles and worn out? Nah, not a chance.

I'd take a look into replacing the coolant temp sensor (bother, is that what it's called?)... If you have a shop manual, I'd hope there would be a procedure for testing it...but if not, I think it cost about $60 or so...

Also, it's pretty easy to get to, by the distributor you'll see the coolant hose coming in to the block...there are a few sensors there...

Sorry, not too helpful...not properly caffiennated yet...

Bogatyr

 

[Jeff]

700 RPM is fine for the idle speed, however obviously it should not shake. Is it just a physical shaking, or does the engine sputter and act like it is going to stall? Did you clean out the throttle body intake? What kind of engine flush did you do?

 

[bmorton]

I've actually got mine going into the shop for maintenance this week and was planning to have them look at it for a similar issue.

Idles smoothly in park or neutral, but in drive it drops down to about 500 rpm. The tach needle wobbles and you can feel it running roughly.

Searched the web and although this seems to be a common problem with all sorts of cars there are a lot of possible causes, everything from a vacuum leak to ignition to bad EGR valve. At only 51k miles I hope it's not anything too serious but looks like a fun one for the techs to diagnose.

 

[jamezckf]

Bogatyr, I haven't got the time to check the coolant temp sensor yet~ Well, to be exact... I have no idea where the coolant temp sensor is, but hopefully by this weekend I will have the time to check it out~~ Thanks for the information, gives me some hope ^^

700 RPM is fine for the idle speed, however obviously it should not shake. Is it just a physical shaking, or does the engine sputter and act like it is going to stall? Did you clean out the throttle body intake? What kind of engine flush did you do?

Jeff, the engine shakes physically, and at times the engine would go so LOW that it actually stalled for a automatic....... I'm going to try cleaning out the throttle body intake. As for the engine flush, I purchased a "Pyroil Engine Flush" from Kragen. Followed through all the instruction in the back. However, the same problem still exist. It was really frustrating me errr....

Bmorton, if it is possible, can you tell me what they checked for the maintenance? It would be great to hear from you!!! Thanks

Thank you everyone, I will have to check it out this weekend

 

[nl4jy]

same problem here. have it for 5 years, only 61k. sometimes it startup fine, over 1k, sometimes drops really low and feels like it's choking.

 

[bmorton]

Just got back from the dealer. Unable to duplicate my rough idle complaint so they didn't do anything about it.

However, they did say that if I wanted to pursue it further that the first thing they'd try would be to check and clean the throttle body and IAC valve. Two hours' shop labour for that job. I said I'd think about it since running a little rough at stoplights isn't a major problem.

 

[Mindscape]

Does your gas pedal also stick when you're pulling away from a stop (ie, when you haven't been using it for 30 seconds or something)?

If so, then it's almost certainly your throttle body being dirty. A link to how to clean it can be found on this site, here:

http://ralphb.net/RAV4FAQ.html#3.2.4

If the gas pedal's sticking, I'd say check the throttle body first, and that'd most likely be the problem. If, though, your pedal's not sticking, then it might not be the throttle body, and thus you can check other things first.

 

[PJ]

This could also be an ECU problem. I had the same thing happen with another vehicle I owned. It was a symptom that came and went for almost a year and then the ECU failied completely. When mine went to the rough idle it was not sending spark to the number four plug. It showed up on the engine scan as a coil failure but the coils were fine, that led to the computer....just a thought.

 

[jamezckf]

Sigh~ I followed the instructions cleaning the throttle body~ The first time I start the engine, the problem was gone... however, after a few days the problem returned >.<

Anyways, I will keep checking up on my car and search for the problem. If I'm lucky to find out, I will let you guys know~~