Timing chain question

[bikerbomber]

Hey Fellas, I am thinking my timing chain is going bad. But what are some surefire ways to check it without straight out removing and replacing? This is for an 88 c1500 4.3 with probably over 100k miles on the engine.

Before you ask, I believe the timing chain could be bad at the advice of a mechanic friend of mine after explaining how even at 0 deg tdc with the connector off, my truck idles really poorly. But when I advance it over 12 deg it runs like a champ. I have to run for now, but I will get you guys more details as to the items checked and replaced when I get back.

Thanks!