I have an 87 LB9 5 speed. With the EGR connected it stumbles a bit when cruizing or medium-low throttle. When I disconnect it, it is fine. Should I replace the EGR valve or is the computor opening it at the wrong time and how can I tell which is happening? Thanks in advance..

 

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>When I disconnect it, it is fine.<

 

Either replace it or block it off. If you block it off, you will need to have it turned off in the computer or else you will get a code 32 all the time. I have mine blocked and get the code all the time, but since I know what it is....i don't worry about it, but if you go this route it would be wise to pull the codes every now and then to make sure there is not something else throwing a code other than EGR.

 

So it is the EGR valve, not the computer opening it at the wrong time. When I disconnect it (pull the vaccum line off it) I don't get any codes. Maybe its because its an 87.

 

That would be correct.

 

Agreed, I did the same thing.

Same darn thing was going on with my 4.3 in my 97 Full size chevy pick up, felt like a constant surge under moderate throttle conditions.

I got some thick Garlok gastet material we use for steam flange gaskets at work, and made a new gasket with only the two bolt holes in it, effectivly using it as a block off plate between the EGR valve and the manifold. I am getting the code 32. Took 3 days to throw the code but it showed up yesterday. I don't care about the code, cause the truck has never run better since I got it 4 months ago.

 

IIRC, it took about a week before my car finally threw a 32 after blocking off the EGR. If my truck ever starts acting up, I am going to block the EGR off in it too.