Hello, new here but looking to contribute and gain information. I have a '97 Suburban with the 5.7 Vortec, approx. 230K miles and (has been) still running very strong. About a year ago, it began to start a little hard, particularly if it had been sitting a few days. In other words, it turned over just fine, but would not fire until several attempts had been made. I had already replaced the fuel pump in it shortly after I bought it (about 160K miles). I changed the plugs and fuel filter, and the problem seemed to go away. A couple of months ago, the problem returned, and got worse until it would not start this week. I should also mention that no loss of power has been noticed. Here's what else I have tried: 1) I thought it might be a fuel problem, particularly because it sits a lot and the tank is rarely full. So, I ran a bottle of fuel system cleaner through it (one designed for large vehicles with 35+ gallon tanks) and completely filled the tank. No real change noticed. Shortly after this is when it quit firing altogether. 2) Checked spark, checked out good. I did notice, however, that a couple of wires had rubbed through each other a bit and were arcing. Replaced wires with a brand new set. 3) Took readings on coil with ohmmeter. Results were somewhat inconclusive but seemed to be okay. Went ahead and put in a brand new coil, anyhow. 4) Changed fuel filter (again), even though I changed it less than 6 months ago. Verified that I am getting fuel at the engine with my fuel injector pressure gauge and relief valve. 5) Put in a brand new distributor cap and rotor. After all this, it still turns over just fine but will not fire. One person suggested to me that maybe the timing chain jumped, but this does not make sense to me, since the symptoms have been present for some time, yet the engine ran like a top and started easily once the engine was warm. With a timing chain issue, I would expect (at minimum) a rough idle, missing, or a bent valve(s). The onboard computer is not throwing any codes.