Ihave camry 00, 4 cyl with 83K miles bought 8 months back with 75k miles on it. Before buying got it inspected by PEPBOYS and was OK.

Last monthonwards I have this weird problem. During peak traffic in city roads, After few quick stoppingsat the stop lights or frequent acceleration and brakings, the engine starts vibrating and miss firing. The RPM indicator also vibrates. Once I start moving looks Ok but not smooth. Vibration does not stop even after parking the car. Once I shutdown the engine and re-start after few minutes, car runs smoothly. This does not happen everyday but happens atleast couple of times a week

I took the car to my mechanic and he changed all the ignition stuff, spark plugs etc. But still the issue was not resolved. Subsequetly he said that the vibration is because of shocks and struts and I got them replaced also. Still the issue is not solved and I am worried now.

Can anybody please help me to understand the issue and correct it ASAP.

 

The 4 cylinder always has a little vibration at idle, worse as the idle RPM drops below what it should be. Is the engine really misfiring or is the idle just going up and down. If the idle what is the RPM range? When the engine runs OK at idle, what RPM is this?

The car has electric radiator fans. In stop and go driving the coolant temp will heat up enough to cause the fans to kick on. This typically causes an increased alternator load, which may vary the idle speed a little. The next time the idle starts to vary determine if the radiator fans are running, watch the engine itself to determine if it is shaking. The engine mounts may have a problem.
There should be a valve controlling the idle by bypassing air around the throttle body. Perhaps the valve is not responding quick enough and causes the idle to start to hunt.

Shocks and struts have nothing to do with this problem. The engine mounts isolate the engine from the chassis.

 

Hi Toyomoho, thanks for your inputs.

In normal idle the RPM is 600. When the problem happens the RPM fluctuates between 400 and 1200/1400. I thought it could be misfiring or some sort of fuel line problem.

Next time it happens I will check for the radiator fan. Should I ask my mechanic to check the valve and engine mounts ?

Is there anything else I should be doing ?

Thanks..

 

Hello Camry experts,

I still have the problem which is getting more frequent now. Yesterday when I took the exit out of freeway (70mph) in the noon and was trying to stop at the traffic light, then car started vibrating, the tachometer was oscillating and I had to slam the brakes very hard to stop the car at the lights. I had this again at the next traffic light about couple hundred feet from the previous one. I did not see the any indicator in the dashboard. the thermometer reading was at the center as usual.

I took the car to the mechanic and left it with them for a whole day. Inspite of several test rides, they could not simualte the symptom and they also mentioned that the computer diagnostics indicate everything Ok. there was no code stored in the computer when the failure happened it seems.

They have no clue on what is happening and say that only when they can see the symptoms they can correct the issue. I have no means to simulate as it happens randomly and does not repeat after few minutes.

The mechaninc mentioned the power brakes did not work because vaccuum gets shutoff when the engine was stopping which is whay I had to apply manual brakes which is very hard. Is he correct?

Please help me to understand the problem and correct it. I suspect some thing is getting heated and makes the car to stall, but I am a zero in car mechanics.

Please help,
00CAMLE

 

One thing to keep in mind is not all the cars systems are monitored by the computer. Thus it is very possible a part has a problem but because it is not monitored there will never be a code set.

The computer monitors the cars systems over time. Some problems are required to occur 2 times before a code is set and then must occur within a certain set of parameters such MPH, RPM, coolant temp.

The computer looks for variations in sensor voltage, current, etc. output but only when these parameters are met. Otherwise codes would be tripping when the engine was cold started, at full throttle, etc. Conditions that are not typically for 98% of the time the car is being driven.

The ODBII system was mandated by the EPA to monitor emissions systems, alert the owner to possible problems and rapidly diagnose them. The system does have codes to warn of some types of engine misfire.

If the engine dies when driving, vacuum to the brake booster does also. The result is no boost and much harder breaking. The brakes themselves are still working normally, the issue is you now need to really press on the pedal because there is no longer boost helping your foot.

The car is still safe to drive If you keep in mind the extra foot pressure needed to stop.

If the temp gauge reads OK unless defective the engine is not overheating.

If the engine dies after releasing the throttle would look at the air valve (IAC) and fuel system.

If the engine hunts at idle would look at the throttle possition switch, A/C idle up system, IAC valve, MAP sensor, fuel system.

The common issues are IAC valve and fuel system, not all of the full system is monitored, the IAC is not monitored. Thus no code can be set for some problems.

IAC valve issues are common. The symptoms can be high or low idle after engine start up, hard starting, idle hunting, engine dieing. But once the engine dies, it typically starts up just fine and runs OK until the issue reoccurs.

Do a Google search on "cleaning IAC valve." You should find numerious hits, some may have photos. You can try this yourself with only a few tools.

If interested in trying this post back for more info.

 

Thanks a lot for the info on the computer diagnostics and suggestion to check the IAC valve. I checked google and have some information.

Appreciate if you can give more inputs on the same

Thanks once again.

00camle

 

Check out these posts.

https://www.camryforums.com/m_3580/mpage_1/key_/tm.htm

http://www.funbolt.com/articles/toyo...l-valve-49645/

http://www.toyotanation.com/forum/sh...amp;forumid=15

 

Thanks for the info. Suggested by you I did the google search and found that this problem has happened to lots of people and the causes are several too. I noticed the problem got resolved with one of the following. There could be more causes than what I found.

1. replace coolent temperature sensor
2. change ignition coil,
3. clean IAC valve,
4. replace IAC valve
5. clean sticky EGR valve
6. replace EGR valve
7. replace EGR Vacuum Modulator
8. replace MAP sensor
9. replace ignition coil
10. replace distributor cap and rotor
11. jamming of flap in the air intake system
12. vaccum line
13. replace ECM

Since the list is overwhelming, Is there a way I can eliminate some of the above based on symptoms ? Then I think I can start with cleaning IAC valve first, but appreciate if you can prioritize the sequence I can follow.

Thanks a lot for your help !!!
00camle