Hi everyone. This question is not about my Camaro, it is about a Gmc truck I am restoring for my son. I rebuilt the 305 recently and it has been running great . Then , yesterday I put a different throttle return spring kit on it. After that it started running really rough , even stalled a time or two. Now to put this spring kit on, I had to keep throttle pushed back the whole time, which had choke plate open , so I am wondering if I allowed some trash in. It is running better after letting it run some and adjusting idle screw, but, still not right. I used temp gun on exhaust ports while it was hot and numbers 3 and 5 were not nearly as hot as rest, so if trash got in, would it cause a mis in 2 cylinders ? I'm not sure what else could have went wrong so fast , if all I did was put spring kit on, any thoughts?