Hello all. Joined the site to help my dad out. I am an industrial electrician and certified level 1 Chrysler technician. I have a certified Toyota technician buddy helping as well.

Truck is a 95 T100 SR5 2wd. 3.4 automatic.

We have a misfire on cylinder 6 and cylinder 4. And a random misfire code. We have reset the codes at least 4 times via a scan tool or disconnecting the battery while performing an attempted repair or troubleshooting. Same codes return every time.

Swapped ignition coils, also checked resistance in coils and wires. Removed plug and visually witnessed very good spark.

Replaced injector on cyl 6. Initially only cyl 6 was misfiring. 4 started after replacing 6's injector.

Removed and tested all injectors. All work and spray properly. Also used noid light to verify power and ground at connector. Have 12.6 volts on the black wire, ground wire checks good with ohm meter between connectors at injectors and ECU.

Removed valve cover and witnessed cam and valves operating. Timing is good. Timing belt is in good shape as well.

Compression is 150 psi. Have replaced the ECU. No other cylinders misfiring. Just 6 and 4. 4 almost seems to be intermittent. 6 is a dead hole. Removed spark ply from 6 and 2. Placed paper towel over plug hole in 2 and cranked engine. Towel got wet with fuel. Placed over 6 hole and towel stays dry. Remember....noid light lights up on injector connector and injector is new and function has been verified. Fuel rail has been flushed as well. Have replaced spark plugs also. Plug wires and timing belt are about 50 k miles old without issues.

Thanks in advance for any and all suggestions. We are stumped. Been a good truck so far.....

 

Guessing you checked your valve lash?