305 running lean! HELP!

[black96]

Ok, I have a 96 SB with a 231,000 mile 305. I FINALLY have all the parts to swap my 383 in. So, I I installed the headers this weekend so I can get exhaust taken care of. This way I dont have to start a new motor open headers and can listen for potential problems. I already have a westers tune, and will have the ecm re-flashed for the 383. When I pulled the plugs I noticed 3 of them were showing a lean mixture, the rest were fine. I have had this truck on a GMtec-2 scanner recently and it showed the a/f ratio at 14.7 consistenly until acceleration, then it richens normally. With this many miles I wonder if my injectors are getting weak? Maybe I just need to clean them before bolting the intake on the 383? This situation is kinda scary, I would hate to burn up the new motor because of this. Has anyone seen this before and what is the cure? I plan on doing a marine intake swap sometime in the future. I would sure like to be able to install my 383 before I dive into the marine intake swap. Thanks in advance for any help!

[98GreenMachine]

When you say you have a Westers tune, do you mean from before the swap or after the swap? Did he adjust fuel tables accordingly for the increased cubic inches? How old are your upstream O2 sensors?

Assuming you still have the original poppets, 231k is alot of miles for them. If you are going through the trouble of a fresh rebuild, me personally, I would get the new Multec 2 injectors GM released awhile back. Its possible your FPR is bad, the new injectors come with a new one.

I'm not saying the new injector set will cure your lean condition, I'm just saying it would suck to have your old set fail on a new engine. On the flip side, it very well may cure it.