Lexus Sc400: Car Cranks But Will Not Start!

[rhodogg23]

I have a 1993 Lexus SC400 with about 170,000 miles from it. I bought it from a private owner and he does not have any papers on his previous maintenance. The only problem that I have with the car is that the Car does crank but will not start. Eventually after 10 minutes of repeated cranking it will eventually start. I took it to an autoshop but they couldn't diagnose the problem. All electrical instruments in the car works. Another concern of mine is that when idle, (when stopped at a red light) the car would sometimes have a rumbling/engine surge, sounds like its coming from the exhaust? It would eventually subside when driving and when I stop againk, same thing happens. Any help would be useful.

[arielscar]

I'd check timing first - then maybe a main computor failure.

[Air Force Rascal]

I'd check timing first - then maybe a main computor failure.

You might want to check your Catalytic Converter or EGR valve..cats may be clogged up..just a thought!!