Intermittent Rough Running

[Bigrick]

For a while, my '97 ES300 will, after fully warmed up, start to run very roughly. If I shut it off and let it sit for awhile, it will start sluggishly and then run perfectly for several days. At first this happened about every 3 months. But now, it does it every 5-10 days. It does not seem to be affected by the weather. The dealer service advisor says that I should bring it in when it happens again, but this is easier said than done. The car has 102K on it and has had all maintenance performed by the dealer. Does anyone have any thoughts on this? Thanks!

[steviej]

check the easy stuff first.

The black acordian-like tubing that goes from the airbox to the intake manifold is prone to hardening due to the heat under the hood. When it becomes hard, it becomes brittle and may crack or get small holes. These openings let more air in than the computer knows about and makes the engine run rough. Check this hose all over.

Other areas to look for would be a dirty throttle body, dirty fuel injectors, and a dirty idle air control valve.

steviej

[pete1rayce]

check the easy stuff first.

The black acordian-like tubing that goes from the airbox to the intake manifold is prone to hardening due to the heat under the hood. When it becomes hard, it becomes brittle and may crack or get small holes. These openings let more air in than the computer knows about and makes the engine run rough. Check this hose all over.

Other areas to look for would be a dirty throttle body, dirty fuel injectors, and a dirty idle air control valve.

steviej

I too am encountering this problem. I have a 92 ES w/159K. It started yesterday. I thought it was a mis, but it is not harmonic like the same cyl missing each time, it is intermittent, and does not seem to be influenced by anything. It comes and goes and seems to muffle or interrupt ALL or any cylinders.

I can't figure out if it is a fuel system problem or an ignition system problem at this early stage.

Does anyone have any suggestions beyond the advice on the IAC / Black tubing?

[pete1rayce]

Ok.

I have an update......My distributor cap was cracked, the air intake hose ( Black Corrogated One ) was / is cracked ( not sure if I did it, or it was like that) but never the less, I will be fetching these parts and putting it back together and I'll let you know.

[Bigrick]

It was the EGR valve. I was able to get the car to the dealer while it was acting up. Tech tapped the EGR valve and it ran smoothly. They replaced the EGR valve and I have not had any problems since. Total cost: part $213 + $45 labor. This may be a good way to rule out or confirm a bad EGR valve.

[pete1rayce]

It was the EGR valve. I was able to get the car to the dealer while it was acting up. Tech tapped the EGR valve and it ran smoothly. They replaced the EGR valve and I have not had any problems since. Total cost: part $213 + $45 labor. This may be a good way to rule out or confirm a bad EGR valve.

Good to know Rick,

I am just thankful for this forum, I read a tidbit here and there and it got me looking in the right direction. My car is running like a top again. By the looks of it, the distributor cap had been cracked for a while, and over time moisture had built up inside causing all sorts of problems. I am not the origial owner of this car, so sometimes I don't know what was maintained and what was not.