A problem with my car developed over the weekend (1996 Bonneville SE Standard 3..

It'* got a real rough idle which is especially bad at slow speeds and when I come to a stop. The car seems like it wants to die when I come to a stop. I brought it to AutoZone and had him plugin the diagnostic computer they have and it came back with cylinder misfire and EGR valve.

He said to replace the spark plugs and wires which I did, problem is still there.

The fan isn't running... I haven't noticed this problem before, and the temperature gauge has never displayed anything more than 210ish. I unplugged the thing that plugs into the radiator fan and it looks just fine.

The car is also running low on oil. It'* leaking out of the right side of the engine block and my friend who'* fairly knowledgeable about engine told me this is because the engine'* overheating and causing the oil leak. He also said the cylinder is not misfiring and it could be a problem with the fast idle?

I could really use some help on trying to pin down what these problems are... if you need to know anything more please ask and I'll try to provide the best details I can. The autozone computer was wrong about the misfire, but does it sound like I need to replace the EGR valve?

My first thought is a vac leak. These tend to give odd unrelated error codes. Including misfire, lean, EGR, and a few others. So first thing you need to do is search for a bad vac line. do this with a can of throtel body cleaner, spray that on the connections and hoses while the engine is running. If RPMs go up, you have found the leak.

The only time the fan is needed is when your not moving. So unlikely it'* over heating when driving. What happens with your temp when driving?

I've never noticed excessive temperatures when driving. It has always maxed at 210ish and stayed there, perhaps fluctuating slightly under that level and back again. I check the instrument gauges every time I drive, perhaps every 10 minutes I do a full read on all gauges, and I've never seen it exceed this level. While my friend and I were taking a look at the engine today however, in park, he was adjusting the throttle boy revving it up and such to see if he could figure out what the problem was. The fan never turned on and I turned the car off to prevent overheating.

As for the vacuum leak, is this something that can be easily self-repaired (I can do more basic things), or is it something I'd have to bring it in the shop to have done? Any idea on pricing for such a repair?

You can fix a vac leak with a new vac line. You can get a pack of that from autozone or other parts store. Price is $10 ro $15 or so. You just cut it the the length you need and hook it up. Real easy.

Your car should have a 195* thermostat so 210* is about right.

Which hose exactly is the vacuum line? Is it the one the leads from the bottom right out of the unit that houses the air filter?

http://home.cfl.rr.com/meangt/parts/...%20(Small).JPG

With the radiator fan, should it be running all the time while parked, or will it only kick in once a certain temperature threshold has been reached?

There are vac lines all over. Most of the hoses are vac lines, excluding radiator, heater, and fuel lines.

In this picture the vac lines are kind of orange. This is a supercharged engine so yours will look a little different, but you should be able to get a general idea.


The fan wont run all the time. Only when it reaches a preset temp and is there for a preset time.

Let'* back up a moment and rethink this one.

Autozone told you the EGR had thrown a code, do you know which code? That would be helpful.
The EGR meters air into the engine, behind the maf sensor. This means that essentially it is a vacuum leak. Usually metered. If stuck open then your engine will run poorly and probably have misfires.

It is unwise to listen to the folks scanning your car unless they are a dealership that services the type of car regularly. The guy that told you to get plugs and wires probably gets paid $8/hr to sling parts, no offense intended..it doesn't sound like he was overly qualified to diagnose the car for you. =0)

An EGR can be removed and possibly cleaned. Using carb cleaner try to free up the pintle valve on the bottom of the EGR. It should move in and out freely w/o any binding at either end of the movement. Remember to wait until the EGR is stone cold to do this. otherwise it may be too hot to handle.

I'll remove the EGR valve today to see if the valve is stuck at all.

Do either of you know if it'* common practice for members near one another to have work done in a backyard mechanic setting?

If the problem turns out to be something I can't fix but another member could easily do I'd rather go that route than pay out the nose to a shop.

That depends on the member. Bill does it a lot, and so do I. I just did a 4 wheel brake change last night.

Heh, I guess it'd have to be somebody nearby Minneapolis, MN.

Perhaps it might be a good idea for a section to be opened under the Buy/Sell/Trade section for members to advertise for mechanical work?