I have an 87 5.7 TBI GMC Burban.

I am current having a very ruff idle and cold start issue. The cold start has been going on for some time and I have done a few things already. Today the ruff idle started and it is also blowing black smoke and wants to stall. It runs when driving pretty well. However when you get to a stop sign the engine wants to shoot out of the hood. It idles very high and if I rev the engine in park the idle will go up and stay up.

Now I just did the spark plugs today. Which where bad but was not the issue. The timing has been recently set and the pcv was replaced. Also the coolent temp sensor was also replaced.

I am wondering if this could possibly be my fuel pressure regulator? up until today it never blew black smoke before. It was running 100% perfect yesterday. With just the cold start issue.

Any thoughts?