2003 Impala Code p0404

My Chevy began hesitating when taking off and when driving straight runs you can feel the car jolting a bit. The check engine light comes on intermittently. Took it to have the check engine light checked and it came back a p0404 code. The kid at the mechanic shop said it was the egr valve and to replace it was a bit over 300. I thought it sounded high so I declined to have it ficed just then as I wanted to look up this issue. After reading many items it says this could be multiple issues including an o2 sensor. What is the best way to troubleshoot this issue to narrow it down? It just recently failed inspection for the code p0404 as well. Money is very tight right now and I cant afford to pay 300 and to not have it resolved the issue.

Anyone?

$300 sounds about right. Which engine do you have, since the EGR is cheaper on the 3.4, but much harder to change. Also you might want to look at this first:http://www.naioa.com/v2/modules.php?name=Forums&file=viewtopic&t=16657&highlight=p0404

Thanks. We have the 3.8...more expensive but sits right on top of the engine. The CAT was replaced not long ago I would HATE to think it is plugged again.

I replaced the intake gaskets on my '02 3.4L last May and I thought the EGR on MY engine sat up top with just a couple of bolts holding it in - real easy to replace. I've got this same code on my Impala right now ... haven't done anything about it yet. Car still runs smoothly, although probably with lower fuel economy. I was thinking I'd pull the EGR and clean it - something I've heard of people doing (with some success). Just haven't got around to it yet ...