I bought my 95 sc400 6 months ago. Needed struts and tires and a key. Did the necessary work and drove it for a couple of weeks. Then it would not fire. Turns over but will not ignite. Tried a ECU, igniters, 12v fp bypass check cam sensor and crank sensor. I then grounded the alarm system, nothing. Unhooked the battery in frustration and let it sit a week. Hooked the battery up and she started up. Drove it for 2 days no problems. Went to start it and now I have the same problem, cranks but will not start. I tried a new crank sensor but it isn't the problem. Any help or suggestions would be appreciated. I just want my car back on the road.
Read an article today from a mechanic that had the same problem with a car he was working on and never got it fixed. UHHggg. Please help if you can.

 

aftermarket alarm?

 

I removed the aftermarket alarm and grounded the factory to disarm. It is going to be a day of wire tracing.

 

Check all the ignition components today from ECU to everything for ignition. Think it may be a problem between the key ignition and the alarm.