I have been dealing with an intermittent and annoying issue with my truck for the past 8 months now. I had been running the TRD Supercharger with Supra Injectors and a Unichip tuner for about a year with no issues what so ever. I then started getting this issue where sometimes I would start the truck and it would fire but then stall and die. I would then restart it and it will crank right back up, but with a P1300 check engine light code. I swapped igniters with another 4Runner but same issue. Took it to my toyota tech and he said the continuity between the ecu and igniter is fine. He suggested swapping ecus with another truck to see if it fixes the problem or possibly the unichip might be the issue.

Anybody have any ideas with what might be causing this issue? I don't have access to any ecu's that match up with mine to try and swap in. I have read several threads about this, but nothing has really turned up an answer. The truck also seems to be down on power and mpgs after having this issue show up.

 

Try replacing your EFI Relay?

Other than that it could be the coil.

ALLDATAdiy.com has the complete trouble tree from Toyota.