When this happens, look at your immobilizer light (little red flashy truck icon by the clock). If you don't have security clearance it will crank but not fire. Sometimes a new ECU fuse improves it. If it's cranking and that light is on then the immobilizer is the likely issue.
EDIT: it's not that the fuse burns, just corrodes enough to drop the voltage a hair or add some noise, wierd I know, but a popular 'mud fix.
Andy | Longmont | TLCA#22354
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-1999 UZJ100 -Black, Ever Evolving, now with SLEE SHOCKS!!
-2001 Tacoma 2.7L Reg Cab 4x4 -Silver,my DD/all purpose truck, mild build so far.