== ? IAC(1), IAC(2) or EGR ? ==

[djFremen]

8) Engine Lopes while Idling or Idles erratically.
a) Vacuum Leakage **Checked**
b) Leaking EGR Valve **Completely removed / cleaned**
c) Air Filter clogged **Removed and cleaning intake**
d) Fuel Pump no delivering fuel **Checked**
e) Leaking Head Gasket **No Leaks**
f) Timing belt / pulley worn **Replaced all belts**
g) Camshaft lobes worn ** Haven't checked **

So, if I don't have a vacuum leak - could I have a bad EGR (Exhaust Gas Recalculator), IAC (Intake Air Control valve) or IAC (Idle Air Control valve).

Things I have done. Tune up 2k miles ago- sparkplugs- wires- rotor- even replaced entire distributor. Cleaned out throttle body 3 times, IAC (sprayed down tube next to throttle body) and replaced the PCV valve (cleaned hoses around it). I checked for cracks on all hoses... They look good.

When I drive the car it idles erratically. A sound like a bump happens and then the RPMs dip, the steering wheel shakes, the lights dim - then comes back up. It feels like it is running on 5 cylinders. I really don't want to take it to the "stealership" cause I love DIY stuff like this, but I can't find the problem. Has anyone had an idle problem like this? Could it be a sensor somewhere that I don’t see? What else could cause this?

[89SV21]

Could it be a problem with the MAF? Perhaps the MAF pickup wire is dirty and its not properly reading the amount of incoming air causing your car to run excessively lean and then misfire.

[djFremen]

Where is the MAF? Is this a sensor? How do I go about checking this senario? Thanks.

[djFremen]

Anybody?

[Tony the Tiger]

You can manually check to see if your EGR is leaking/faulty by the valve to see if it's stuck open. If not, then chances are that your EGR valve is fine.

I would check to see if there is an air leak between your MAF and your throttlebody. Do you have an aftermarket intake? Usually what happens when there is a leak between the MAF and TB, the car would run slightly leaner (unmetered air going to the engine) and cause the idle to fluctuate.

You can also check your coolant level as well as check for air in the system. Sometimes if your coolant is low, the IAC valve will not receive full coolant and will cause the idle to fluctuate. This never happened to my Camry before, but it happened to my other car (Integra) before.

Those are just the "oddball" stuff you should check out, seeing that you have basically inspected and checked all the common sources

[Ratko]

djFremen: your car actually has an AFM (flapper), not a MAF (hotwire). But regardless, Tony is right, if there is a leak in between your air meter and the throttle body, it would affect idle.

I actually have the same problem right now. 275,000 kilometers on the engine. However it doesnt happen EVERY time the car starts, just occasionally. Either way its exactly how you explained.... a hesitation, a large dip in rpm to about 400, then it goes back and forth to about 1200 rpm, then finally settles on something around 1100-1200 rpm (much lower than it should be considering the temp of the engine is dead cold).

[djFremen]

Tony: Thanks man, I will check those things! I never upgraded the stock intake. The coolant level might be a smidge low. Before I take my Camry anywhere, I should disassemble the intake again and the throttle body... Make sure there are no leaks. Maybe I could spray something on there to see if it bubbles (leak). That’s how you check a leaking vacuum hose anyway.

Ratko: Yes, same thing happens when I start my car, the idle dips and sounds like it’s about to stall. After a while, the idle shoots back up to the Cold Start RPM.

Here is an interesting thought. I tested this once and it worked. The problem doesn’t occur if I hold the throttle down to 1k – what if I manually adjusted the idle to 1k? What negative effects would that have on the engine? Thanks again for the replies.

[Tony the Tiger]

Originally posted by djFremen
Tony: Thanks man, I will check those things! I never upgraded the stock intake. The coolant level might be a smidge low. Before I take my Camry anywhere, I should disassemble the intake again and the throttle body... Make sure there are no leaks. Maybe I could spray something on there to see if it bubbles (leak). That’s how you check a leaking vacuum hose anyway.

Here is an interesting thought. I tested this once and it worked. The problem doesn’t occur if I hold the throttle down to 1k – what if I manually adjusted the idle to 1k? What negative effects would that have on the engine? Thanks again for the replies.

No prob Anyway, there are negative effects associated with high idle speed and automatic transmission. If you manually adjust the idle higher, it would cause your transmission to run hotter (more wear), your brakes will become less effective, and of course, more emissions. The fact that the auto trans is always slipping or engaged even when the car is stopped, it would be equivalent to holding your brakes and slightly on the gas at the same time all the time. This also affects the braking as I said earlier because the car is trying to move forward and you are over-powering the high idle with your brakes. Adjusting the idle higher only masks the problem and not fixing it... no good

[djFremen]

Good call about the coolant man... I think one of the lines must have been clogged. Topped off the radiator and cleaned one of the hoses and the idle is much better. Yet, every now and again it still dips. I also noticed that my IAC gasket (by throttle body) was leaking carburetor cleaner mixture. I tightened those bolts on the IAC unit and hope that wasn't the issue. Other than that, it still sounds like its running on 5 cylinders, I think it's time to replace the spark plugs / wires again. Sheesh, I just had Toyota do it... Maybe it's time I do it. About raising the Idle, I never thought of all those negatives associated with raising it- I would consider it if I had a Manuel transaxle. Well, thanks again Tony, I think you were right about it being a coolant problem.

[Tony the Tiger]

Originally posted by djFremen
Good call about the coolant man... I think one of the lines must have been clogged. Topped off the radiator and cleaned one of the hoses and the idle is much better.

[andre123]

Hi guys am having idle problems with my 93 camry 4 cylinder. The lide seems to go up and down slowly when i am at a light. It evens starts like its going to stall then it shoots up. After the engine is hot and i stop the steering wheel shakes and sometimes it doesn't even show up I had to change the head gasket like a year ago and i put on a new timing belt and new TPS. I advanced the timing a little so it won't show up that much. But i would just like to fix the problem when i put it on the computer nothing comes up so I have no idea what to do.

[Stealth]

I've been having a similar problem with my 95 4 Cyl (130k miles) myself. The car stalls sometimes too, usually only after the engine heats up (when it idles around 800). My upper air duct is turn right next to the throttle body, could that be causing it to stall? I had the ISCV replaced last week but that did not solve the problem. Is the IAC another part that I should check/clean/replace or is the same part?

What do I need to do the check the EGR valve on my car (5SFE) and what should I use to clean it out?

Also, sometimes the engine won't crank right away like it normally does. Usually happens after it stalls. I have to try to crank the car like 5-10 times usually. I normally crank in 5 second bursts. I think this is because the engine is flooded.

I had the timing belt, water pump and accesory belts replaced about 10k miles ago.

[chronoti]

hummm dont you guys read other threads on here

but check the coolent temp sensor that would give you warm idle problems, look down a few threads there should be one coving this

[andre123]

I put it on the computer and nothing came up, I checked every sensor and no codes came up. I was thinking its a vaccum leak. This problem is just bothering me that I can't find it.

[qprint]

How do you test the EGR on a 1MFZ V6 Gen5 ?