Bad idle

al_ngl · 06-28-2008, 04:42 PM

My car has a loping, uneven idle. It has been this way since mid-winter, but I have put it off until recently.

I have done a few things to try and fix the idle. I know my timing was correct when I installed the timing belt, but it could have skipped teeth. All cylinders fire. There are no codes being thrown. Upon disconnection of the MAF and/or O2 sensor no change is noticeable. The MAF, IAC, throttle body, vacuum lines, and intake have all been cleaned. I have kept up on all engine maintenance. I have also reset my TPS after adjusting the idle screw. The hottest the temp gauge ever goes is about 150-170 (est.), but the Idle is usually just as bad when the engine is warm as when it's cool. For complete information, I run 5w-30 Valvoline oil and 93 octane gasoline. The only things I can imagine being wrong are skipped teeth on the timing belt, poor spark, fuel problems, a sensor problem, or low compression. Please suggest any ideas to fix my bad idle, it sounds/feels like a junker.

sleeper_inc · 06-28-2008, 05:19 PM

Check your codes. It could be a bad cat or it could be a vacuum leak.

al_ngl · 06-28-2008, 07:49 PM

I think it is the cat, actually. I know it's the only part of the exhaust (except manifold) that has never been replaced. Hopefully my parents will pay for it, but if not, I'm going half-assed and clamping a pipe there

.

And I'm pretty certain that I have no vacuum leaks, when I ran seafoam a couple weeks ago the only smoke was coming from the exhaust. No drips or spraying, bubbles etc. Plus I checked with the paper test and my vacuum lines held the paper securely in place. Is there a way to test the cat before I just cut it off?

Can I still get codes even if I know my CEL works?whenever I unplug something it throws a code, but no codes if plugged in.

sleeper_inc · 06-28-2008, 08:22 PM

The only way to test the cat is to blow air through it and see how much of a blockage is happening.

You can still get codes even without the CEL on

al_ngl · 06-28-2008, 10:06 PM

Blow air through it? How do I do this without removing the cat? I'll try and run codes tomorrow.

sleeper_inc · 06-29-2008, 06:44 AM

Umm.... you can't... Put your hand over the back of your exhaust, you should feel a fair amount of force, but if it feels weak then your cat could be plugged. Only 100% way to know is to remove it or if you notice a huge loss in power

al_ngl · 06-29-2008, 11:54 AM

I do have a loss in power that gets worse every few weeks[&o]. Hey what size pipe do I need to put there? My exhaust is stock, and I haven't really done any exhaust work before. Do I need a pipe that gets bigger at both ends so I can clamp it? I know I'm not gonna weld it unless I can find someone to do it. And what are the consequences (not law consequences) of running no cat? Will there be more smoke or something? Louder is okay, but I don't want a ton of smoke or the cops might get suspicious (plus it woud add to the junker-ness.)

al_ngl · 06-29-2008, 03:54 PM

Or should I just gut the cat and clamp it on so that it looks like it has a working cat?

icelandismine · 06-29-2008, 03:56 PM

If the car is running clean (not burning oil, coolant, or running rich), taking the cat out won't cause any smoke. And you'll kill the poor trees.

al_ngl · 06-29-2008, 05:10 PM

Yes, me and my 2.3L 4 cylinder with a whopping horsepower in the 100s are going to melt the ice caps.

Bad news. I didn't know that there are two cats. And the pipe bends to where I can't use straight pipes to remove the cats without bending.

What do I do? A muffler shop won't do this since it's technically illegal. And I don't see how I can gut the cats with the bends in the pipe. And I can't afford to put money into this 4 cylinder (seeing as I'm saving for a new car). Is there some chemical or something I can put down the pipe to clear out the blockage in the cat? Like drano for the exhaust or something. I don't wanna have to drop $200+ on new cats.