94' Rough, shakey idle on cold start

[Krystle]

Update on this issue 10/25/10 - Unfortunately these symptoms led to another blow of the head gasket. Engine seized up on me Saturday, poor ol' girl was leaking anti freeze from front to back. I won't be fixing again...she's going to car heaven. :'( :'(


Hi everyone,

I have a '94 Toyota, 170k, (new motor at 140k) that has been having some really rough idle issues in the mornings when I start the vehicle up. It feels like an old hot rod with that deep rumble feel.

It seems to happen on every start up if the car has sat for more than 2 hours or so. It happens in all types of weather. I've noticed that giving the engine a really good rev up to 3000 for about 2 seconds will smooth it out, then the car is fine and will run fine for the rest of the trip. Or if I just let it warm up for about 5 minutes it'll smooth itself out. I haven't noticed any decrease in fuel economy. What types of things should I be looking for or should I suggest to my mechanic he check first?

I'm really frightened there's something wrong with one of the cylinders or something. I haven't paid off the last new engine I put in so it's a terrifying thought to me. :nono: I've done the ghetto test of putting a piece of paper on the tail pipe to see if it sucks the paper inwards, I guess this is a poor man's way of testing cylinders? It didn't suck the paper in.

Appreciate any and all kind advice. Thanks everyone

 

[rustyrazor]

I can think of 2 things.

First thing that comes to mind is a basic tuneup. Spark Plugs, Wires, cap and rotor. If it hasn't been done in a long time it's probably worth doing even if it doesn't solve the problem.

Second thing that came to mind would be that the cold start time switch isn't working (I think that's what toyota calls it). It's a temperature sensor that tells the cold start injector to come on when the engine is cold. I had a problem with my cold start switch so I unplug it in the summer and it idles rough for a minute which is better than the other problem I was having but that's another story.

 

[Tornadom]

Is it possible that the issue is related to being at 7,800' elevation?

If everything is in place (all vacuum lines and electrical connectors), your ignition items are fairly new and there is no clogging of the air or fuel filters I would imagine it is related to a faulty sensor.

 

[Krystle]

Thank you for the replies! Do you think it could be related to the EGR valve?

I had a check engine light issue awhile ago, they cleaned off some carbon I believe and reset the light that seemed to make it happy but now I'm wondering if that valve is just shot? Would the EGR valve cause a shakey idle and corrects itself after a quick rev of the engine or normal driving?

 

[Chef-j]

Base on my experience, rough idle cause by air flow and fuel.
It sounds like injectors to me, have you ever clean them?

Check the code if you see anything. This is only way you can have communication with your car.

 

[Krystle]

Chef-J,

Since you are leaning towards air flow and fuel do you think the symptoms I describe could be due to a clogged cat. converter? Is there an easy way for me to figure that out?

 

[Krystle]

Updated in the first post of this thread