Rough Idle/Misfire/EGR?

Friends,
We have a 1998 Lumina 3.1. About a week ago we would occasionally noticed a slight rotten egg/sulfur smell (Catl Convert). Yesterday
when the car was started after work it was real hard to start. After that it was a real rough idle but smoothed out when the gas was put on her until she went back down to idle. The check engine light came on. I pulled the codes and they were two P1404's (extended pintle stuck open); P0404 (EGR Flow CKT Range/Perf); and P0300 Random/Multiple Misfire).
Forgive my ignorence but should I replace the EGR Valve or could there 100 different things that would cause this? If it is the EGR is there anything special to watch out for when I change it? I'd be using the Haynes Manual.
Thanks All, Steve
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You might try cleaning the valve and making sure it's getting a good signal. Clear all the codes before restarting. If replacing, either write down the part number or bring your valve to insure an exact application match.
Hope this helps.....
Dave S(Texas)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You need to clean the ports that feed the EGR valve. It is common for them to carbon up over time. You may also have to clean the throttle body and pintle since you also have that code. They also tend to build up sludge on port injected cars because no fuel goes over it to clean it....

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Friends,
I tried cleaning things up as best I could and cleared the codes. The car may be starting easier but it is still very rough at idle while in gear like at a stop light (car visibly shakes) . Woody I'm not 100% sure what you mean by the 'ports that feed the EGR valve'. Although the 'Check Engine' hasn't come back on yet I had the scanner read codes anyway and at this point it lists the P0404 and P1404.
I asked about it at an Auto Parts store and the guy said it could be the EGR, Catl Convert, or OX sensor (although the OX sensor usually will give a code indicating that). He suggested I go to a Service Station and have them hook up with one of their better scanners to more localize the problem before I spend $160.00 on an EGR. I then went to a service station and made an appointment for Friday. They suggested I change the plugs and wires first since that's what they'll do first anyway. He said raw fuel may be getting to the catl convrt. I really don't think it could be that just based on how quickly the idle changed but I'm certainly no mechanic.
In order to change the plugs and wires I have to ROTATE the engine. The Haynes manual kind of tells you how but I have never even seen this done let alone tried it. Is it relatively straight forward? Would it be reasonable to try to get a used EGR from a junk yard to see if that helps? Sorry for all the questions but appriciate the help so far.
Steve
< < < < <
We have a 1998 Lumina 3.1. About a week ago we would occasionally noticed a slight rotten egg/sulfur smell (Catl Convert). Yesterday when the car was started after work it was real hard to start. After that it was a real rough idle but smoothed out when the gas was put on her until she went back down to idle. The check engine light came on. I pulled the codes and they were two P1404's (extended pintle stuck open); P0404 (EGR Flow CKT Range/Perf); and P0300 Random/Multiple
Woody wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
There is a special tool that rotates the engine after disconnecting the dog-bone shaped engine mounts at the top center of the engine. BTW I had a rough idle (like a misfire) on a 92 Lumina 3.1 that would turn on check engine if it idled for a long period but the car ran ok above idle. My problem required a set of injectors (definitely not cheap). Roy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Which tool ?? I always thought that you had to disconnect the bone, put the tranny in neutral and rock the engine forward by hand or with some sort of pry bar
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.