1UZ not willing to start

I'm looking at buying an SC400 that is having starting problems. It turns over and I know it's getting fuel because I can smell the unburned fuel vapors coming out the tailpipe. I doubt compression is the issue since the owner says one day it suddenly stopped (after it got quite cold). That leaves spark, which is supported by the way in which it tries to start, firing erratically but never staying running, even at WOT while cranking. I know timing isn't manually adjustable on these engines.



It seems unlikely that it's a coil, wire, or plug issue as that would cause rhythmic firing rather than erratic. I'm only left with two options, a bad cam sensor/wiring or something distributor-related. Am I correct? I was thinking of going back there tomorrow with a timing light and checking the timing, but I wouldn't be sure what to do if it were off a few degrees.



Thanks for any insight.