1995 Camry V6 Rough Idle

Hello all,

We have an older Camry (1996 V6) with 159K miles on it that we are going to use for my gf’s daughter’s first car. It sat unused for a while and her father is giving her the car. The issue is that when you initially start it you have to keep the foot on the gas or it will stall. It does a bit better when it warms up but it can still stall if you let off the gas quickly. The plug wires look quite new so I expect the plugs are new as well (will confirm with her dad). I pulled the throttle body and it doesn’t seem to be very dirty but I will clean it anyway and change the air filter. What I did notice is when I pulled the vacuum line (I’m guessing that’s what it is, I am not mechanic) it was split longitudinally through the clamp. I am going to replace the hose but am wondering if the throttle intake is fairly clean if this could be the cause of the rough idle. I’ve watched a video on-line that shows how to clean the throttle body.

The battery looks fairly new but I don’t have my voltage meter to test it. I have cleaned all the connections because I have heard that a weak battery or bad connection can also affect the way the engine runs. This Camry doesn’t have a voltage meter, only a dummy light. The light doesn’t come on so I’m thinking we don’t have a problem with not getting enough power to the computer.

I am trying to be a hero here and save my gf some money because this seems to be an easy DIY repair and I’m not a guy who normally works on cars. The car seems pretty good mechanically though some body and interior issues. I appreciate any input as to whether a split vacuum line could cause the car to idle roughly and if there is anything else I should be looking for.

I should add that the car idles at about 500 RPM which seems a bit low.

The problem might be with the Idle Air Control valve.


As the name implies, it controls the engine idle speed anytime the accelerator is released.

You could try removing the valve and clean it with throttle body cleaner to see if it resolves the idle issue. If not, the valve may need replacing.


An excessively low idle can certainly cause a rough idle or vibration. That low idle could also be caused by a vacuum leak or any one of a number of other things.

My suggestion as a first step is to always run a compression test and eliminate the possibility of an engine mechanical fault. If one cylinder is low, or lower than the others in comparison, then one could throw parts at it until hxxx freezes over and not cure it.

With the age and miles what you should be looking for is roughly 170 PSI or higher on all cylinders.
If 5 cylinders are at 180 and one of them is at 130 then there is an internal engine problem.
If all cylinders are comparatively low then a wet compression test should be done to determine if there is a piston ring problem.

I don’t mean this as doom and gloom; just saying that’s it’s a good idea to cover 1st base before worrying about the rest of them. Fix that vacuum line first and see what happens.

If a vacuum hose is split, it can cause idle problems. I would start with replacing hoses 1 at a time. Then clean the IAC. It has 3 coils and 3 wires that run around to the plugs at the rear of the engine. Also, these plugs are supposed to be dual electrode platinum.

I, along with db4690, agree with Tester on this one. The IAC would be most suspect.

Well, replaced the hose and cleaned the throttle body. I might be seeing some marginal improvement but I still think it needs to idle higher. Too late to do much more today with it but I will look into cleaning the IAC next week.

Found a nice video that shows you how to clean the IAC without removing it. Remove the air intake to expose the throttle body. Disconnect the air inlet bleed hose from the crankcase and move aside. Hold your finger over the end of the bleed air inlet and fill the IAC with carburetor cleaner (I’m assuming that throttle cleaner would work as well). Move the flapper back and forth (end point to end point) for 10 minutes or so and drain into a cup. Repeat until clean.

Did it work?

Won’t be able to try it until Saturday. I’m thinking I will go ahead and do the same on my Jeep Cherokee which has 180K on it. It has a tendency to idle a bit rough when cold. It seems you can access and remove the IAC pretty easily on the Jeep. I’ve seen a video where someone just sprays down into a slot in the bottom of the throttle body and it works but the cleaner and sludge then drains into the crankcase which can’t be very good. I also don’t think it would get is a clean as the other method I found and it really doesn’t take much more effort to disconnect the bleed line first.

How old is the gasoline in the fuel tank?

You could pull off each spark plug wire one at a time and see if the idle drops, if it does than put the wire back on and try the next., because that one would indicate its working ok. If you come to one that the engine stays the same then that wire, spark plug or cylinder may be bad.
IF all cylinders are ok, then I would go with what others are saying, and check the emission sensors. Being that the light isn’t on yet, it also could be that air hose your talking about with slit in it. Wrap it with electrical tape as a short fix and see if it changes. Look for other air leaks…

Have you cleaned the MAF With sensor safe cleaner. It will cause rough idle to.

Any vacuum leaks will usually lead to rough idles. So that’s first on the agenda to fix. Since that line has split, the entire vacuum system is suspect and should be checked for air-tightness with a hand held vacuum pump.

Not sure if it applies to your 95 Camry, but my early 90’s Corolla has an idle adjustment screw, sometimes referred to as an “air bleed screw” that I have to occasionally adjust to correct for slight gunking up in the throttle body, which lowers the idle rpm. The Corolla recommended idle is 800 rpm as I recall, which I set when I do a tune-up with the screw. 500 rpm does seem quite low.

Not real old, the car did get used occasionally. But I did fill it up completely and put some injector cleaner in it and took it on the freeway for 20 miles or so. I’m going to clean the IAC tomorrow. I did the one on my Jeep but I still notice some idling issues when hot but I think the thermal shielding is in bad shape, I get a P303 code when I start it hot occasionally. I haven’t noticed any idling issues with it cold since the cleaning but I’m going to remove the throttle body and really give it a good cleaning - it is almost at 180K miles and I don’t think it had been cleaned before I did so (when cleaning the IAC). But with the throttle body vertical it is really hard to see what you’re doing and you can’t really get down in there to clean everything. I bought a new throttle body gasket and a new IAC for the Jeep. I’m getting a new car in a couple of weeks but keeping the Jeep for fun.

Cali, all the plug wires are new so I expect the plugs are as well. We will check with her dad to see if that’s the case. I already replaced the hose and no change. When at speed it seems to run well, plenty of power and no odd noises or actions. It just won’t idle at cold and seems only a bit better once warmed up.

Knfenimore, no. I will look at that as well.

George, someone else said to look for an idle screw as well. Nothing stood out to me but then I am not really much of a mechanic. I’ll have to Google it and see where the hell it is (if it is there). I do think that cleaning the IAC will be the next step and if that doesn’t fix it then at least I can rule it out. The car does have 159K on it and I know the throttle body was pretty dirty so I have to think the IAC needs a cleaning as well.

I would do a sea fome gas treatment and drive it on the expressway using up as much gas as feasible then add 6 gallons of gas more gas and sea fome or techron per directions before I start chasing ghosts.

@Barkydog There was about 2-3 gallons of gas when I filled it up at Chevron and I added some Tectron injector cleaner at that fill up. The drove it on the freeway for awhile. Like I said, at speed the car runs fine, it just doesn’t idle well (500 RPM). I don’t think it is an issue of bad fuel. Cleaning the IAC seems to be fairly simple process and I am going to look to adjust the idle screw.

UPDATE: For those of you who voted IAC you can pat yourself on the back. As soon as I got the solenoid off and disconnected the bleed air line I sprayed throttle cleaner down the hole and into the IAC with my finger over the bleed air outlet. When I first tried to turn the flapper it didn’t want to move at all. It eventually it broke free and I got full range of motion. Moved the flapper for a bit, let it drain and repeated this 3 times. Put everything back together and started it up. It immediately idled at 1500 and after it warmed up it idled smoothly at 750. I am currently enjoying a beer and hero status with the girls. I thank all of you for the help. Next up is replacing the hood lock (their dad ran into something at some point and I thought it was just a cable problem but it looks like the mechanism doesn’t work at all and part of it was bent. Going to replace the hood struts as well since I have to use a piece of wood to keep the hood up now.

Congrats, and thanks for letting us know your happy outcome!