Hey there guys. This isn't urgent, I was just wondering if there is anyone out there who might be able ot explain this one. I notice that:

• when decelerating under 5 MPH to a stop
• when in overdrive and the RPMs fall below 1800 and I give it gas, and
• when idling in gear

that the car shakes softly.

Note that all of these involve low RPMs and when the car is IN GEAR. It DOES NOT occur at idle when I am not in gear, which puzzles me.

It's like the car is a manual and it's lugging just slightly. It's not very bad at all, and some people say it's just the magnaflow and performance Cat that's on the vehicle. I want some real assistance--what do ya'll say? Just the exhaust system, or a bad MAF, or something else? I don't think the engine is misfiring because I just had it in for a whole bunch of electrical tests on the engine.

 

You might want to check the EGR. If it is sticking open you'll have symptoms like you describe.....

 

Maybe a misfire. Check the plug wires.

 

Wrd:

The plugs are fine as per my last post. I just had it into the dealer and they run electrical tests on all the plugs, cylinders, etc etc.

BW:
Ok, will do. That might actually be it. I'll check it out and let you guys know. Thanks!

 

Bad MAF usually exhibits itself at high RPM first, so I don't think it's that.

Do you get any sort of strange behavior when blipping the throttle in Neutral or Park?

 

Hey there Jake:

Nope, not at all. Just spikes the RPMs then falls down to 600-700 rpms and stays there. I'll check the EGR and see if it's open or damaged and check back in later today to let you guys know what's up.

 

What about when brake-torquing?

 

OP.
I must be blind because I dont see where you stated in a previous post that specifically the plugs were fine. FTR I stated to check the plug wires.

I will say again. Check the plug wires and dont trust the dealer. Remove them and Ohm check them. I had 2 open wires that resulted in misfires and rough idle. You can take it or leave it.

 

Wrd:

I no, I appreciate the input -- don't take it otherwise, please. I will go ahead and check the plug wires, then. Ha ha, when I said electrical test in my first post it was running through my mind that they had checked the plugs, plug wires, etc. But you're right, they definitely could have missed something. Let me look again and I will let you know what's up.

As far as brake torquing, I considered that, but that doesn't account for the two problems with shake while moving and I already had the car on jacks and was inspecting the brakes. They look good and the rotors aren't damaged in any way.

 

Engine mounts going bad?

 

Words to live by!

Another good guess, especially since this one won't show itself in an electronic diagnostic.

 

Jake:

I'm starting to get that sentiment! LOL!

Let me take a look at the engine mounts. As far as I can tell the EGR is closed and normal. There is however a very light hiss that comes from near the right side of the radiator. I'm sure it's a hose or something, just haven't pinned it down yet.

 

I have a 1988 Buick Skylark that would shake like crazy when Idling. But when in gear, it would stop. I had bad engine mounts, and had to have them replace. The rubber engine mounts, got very hard. They were made of some rubber material.

 

Yeah, I'm pretty sure this is the problem. It also does it sometimes while not at others, usually in correlation with some temperature change and how I've been driving. In other words, it seems to do it when the engine is running a certain way. Just out of curiosity, but how difficult is it to do this yourself. The word "Engine Mounts" makes me a bit worried!

 

This happen to me over 10 years ago, the car has been in the garage sitting there. But I got my local mechanics to tackle the job. They jacked up the engine, just enough to replace the rock hard rubber engine mounts. For someone that knows, it should be pretty simple.