Ford: ford truck 1990 4.9 Liter In line six cylinder, blown head gasket, mileage vehicle

Question
Cylinders, front to back 1,3 and 5 are dead, plug wires to ground has spark, 2,4,and 6 ok, Compression 155 pds. on #2 and #3 cylinder!

Answer
Hi.

I'm guessing that this is a high mileage vehicle.


I would start with  cylinder leakage test.  You should be able to rent this small tool at your local shop., and on this erngine, the test is simple, but it requires shop air.

I suspect a blown head gasket or valve problem, but it could still be electronic otr injectors