How much variation in degrees of timing at idle would be considered problematic? As I understand it, and please correct me if I’m wrong, due to engine or timing belt/chain/tensioner wear, timing at idle will start to bounce around a little bit. At what point should one start to be concerned? And, upon reaching that point, what is the solution outside of rebuilding the engine? Would replacing the timing belt/chain and tensioner resolve some of the issue? I’m dealing with a 2002 Ford F150 with a 4.2 L engine with160,000 miles (its timing at idle is about 14° +/- 4°), but this could probably apply to most engines.
Being s few degrees off shouldn't be a big deal on an older engine. All that's really going to do is either cause you to lose or gain a tiny bit of power from the engine. If you get way out of time the engine won't run right and you'll know something wrong for sure.
