funniness / shaking at idle

ok, here's the thing, this ONLY happens in the morning, like when I'm going to work, I haven't noticed it at any other time. And it only happens if I bring the car up over 3000 RPM, like if i punch it. which i normally have to do to get out of the neighborhood and onto 40mph traffic. right after that when i'm idling at a light the car shakes like crazy. Unless I rev the engine up to 2500 + then it goes away, but comes back once it drops back down. It doesn't happen if I dont floor it coming out onto the main road, like today. It doesn't happen in the afternoon when I goto lunch, or when I leave my office.

I'm thinking the throttle body might need to be cleaned. but if that was the case, wouldn't it do it all the time, and not just in the morning

[Uncamitzi]

You might just check this out... and let me know if it helps. I didn't notice this at first either. check your two cooling fans. I have one that is slightly out of balance and when it comes up to full speed it shakes the S#it out of the car. The timing of the fan coming on sounds very close to yours. I too, thought that it was a engine issue at first. Still it's not a cheap fix. New radiator 300.00 new fan 175.00 new condenser 250.00 and one new fan shroud 75.00.

When I buy my new one I know how to check things out now..

Originally posted by Uncamitzi
check your two cooling fans.

hmm, this might be the case, i'll take a look and let you know what I find...but shouldn't the fans come on more often? I've noticed them kick in before, and didn't notice any shaking...Tomorow morning i'll take it out, as I normally do, then pull it over and check it out.

ok, i got it to do it again this morning, and opened the hood. it wasn't the fans, you could see the engine shaking back and forth

[Uncamitzi]

Fouled fuel injectors??? I really have no idea....


BEAV!!!!!

[Beav]

The next time it happens try disconnecting each injector, one at a time until you can isolate which cylinder(s) are causing the problem. This is very difficult to diagnose at a distance, it would be so much easier hands-on. I'm guessing that standing on the side of the road, on your way to work, is not exactly where you want to do your diagnosis.

Gotta get to work, I'll try to follow up tonight.

ok, but how do I disconnect the injectors?

[Beav]

It's been a while since I've stuck my head under the hood (and I get so confused these days ) you can unplug an injector or unplug the coil for each cylinder, whichever is easier for you. The main idea is to tell if the shaking gets worse or doesn't change when you do. When you find a cylinder that doesn't make a difference you'll know where to concentrate your efforts.

Originally posted by Beav
When you find a cylinder that doesn't make a difference you'll know where to concentrate your efforts.

wouldn't i want to find the cylinder that makes the shaking stop? IE I unplug cylinder 3 and it acts normal. ?

[Mr. Pockets]

Originally posted by EverclearAtMSU


wouldn't i want to find the cylinder that makes the shaking stop? IE I unplug cylinder 3 and it acts normal. ?

How would unplugging the coil or injector from a cylinder suddenly make the engine run normally?

If you unplug an injector or coil on a normally-functioning engine, the engine is going to shake because suddenly one of the cylinders isn't firing like it's supposed to.

Beav's solution isolates the problem by finding out, when you unplug the coils (or fuel injectors) one at a time, which one doesn't make the shaking WORSE. That one is causing a problem, obviously, because the engine runs the same with or without everything hooked up right. Get it?

Incidentally, I would think you'd want to unplug the fuel injectors, and not the coils. By unplugging the injectors, you're not forcing more and more fuel into a combustion chamber until you plug everything back in. I wonder what happens if you unplug the coil, let the cylinder fill up with fuel from a hundred cycles and then plug the coil back in...

Originally posted by Mr. Pockets


I wonder what happens if you unplug the coil, let the cylinder fill up with fuel from a hundred cycles and then plug the coil back in...

boom maybe?

I think i'll unplug the injector

[Uncamitzi]

there would be a little fuel build up I would think but most would just naturally be expeled by the normal 4 cycle action of the engine. your exhaust might get rich for a couple of seconds. This really shouldn't be a problem.

Just my opinion...... I could be wrong!

[Mr. Pockets]

Originally posted by Uncamitzi
there would be a little fuel build up I would think but most would just naturally be expeled by the normal 4 cycle action of the engine. your exhaust might get rich for a couple of seconds. This really shouldn't be a problem.

Just my opinion...... I could be wrong!

Duh...that makes sense...thanks. :P

I just wanted to say thanks for all your help guys.

I wound up taking my throtle body off last night, pretty easy task till I looked at it. Man, that thing was gummed up w/ so much crap! It took me at least 2 hours, and a full bottle of carb cleaner, 2 tooth brushs, and a roll of paper towel to get that thing cleaned out. Anyways, the results...no more shaking well, there is a tiny hint of one still, but nothing like it was. also I'm seeing better responses from the engine, smoother on the cruse control, and it sounds better too

I guess after 10 years of neglect it had to speek up. Maybe I should pollish it this weekend

[Uncamitzi]

Glad you found the problem, and with no explosion!

Sounds like it was a much cheaper solution than the one I have to do to correct my shakes. (about 1000.00)

Has anyone else noticed that just about everything that goes wrong on this car costs about 1k?????