Intermittent Misfire , please help.

[AzJimbo]

Ok guys, I'm stumped. '03 4x4, mostly stock. So two weeks ago I put a steering box stabilizer and new steering box on my truck. Because of the previous PS leak, I sprayed the area with degreaser, then rinsed with water hose. Directly after, it started to miss, and threw a 204 code. I thought something was just wet, but it hasn't cleared up. I ohmed my inj solonoids, all were under 1 ohm. Now, with my temp gun on the exh manifold, looks like no fire in # 1 & 4. But no other relative codes. Usually runs fine at cold start but NOT if block heater was plugged in over night. Ten minutes down the road, when water temp hits about 200, starts to miss. May smooth out after a while, may not. I've been adding a qt of atf to my fillup, doesn't seem to change anything. I have a chilton book, a DVOM, and tools, but I'm not sure where else to look.
Thank you in advance for your wisdom.

 

[AzJimbo]

+, no chip

 

[Motorhead]

Check your crank position sensor that reads off of the harmonic balancer for loose connections or maybe you damaged it doing the steering box and stabilizer. Check the wire connections to the sensor.

 

[AzJimbo]

Will do! Although no cps code, and the miss is random and intermittent. Thank you for the start.

 

[cerberusiam]

Then it is wiring harness or injector solenoid. Testing the solenoid will only tell you if it is bad at that particular point, after the engine is up to temp it is typical the solenoids start showing intermittent failures with missing and codes if the open\short is bad enough.

Since you did pressure wash it and clean check the 3 injector harness plugs to make sure they are clean and tight then check the harnesses leading to them for scuffing of wires. Water inside the tape and wrap is not going to go away for a while unless temps are high and you live in the desert.

 

[AzJimbo]

After a lot of head scratching and foul language, *I pulled the ecm harnesses off and found a trace of moisture. I cleaned them with an ELECTRICAL COMPONENT CLEANER looks and smells just like carb cleaner, but whatever. Did the injector harnesses too. Got everything clean and dry, applied some di-electric grease and she's running like a hound again! *
Thanks to the guidance from Jeremy at DownTime Diesel in Mesa, Az. That guy is the real deal, and a genuine good dude if you ever need work done in AZ. *

 

[Prairie Dog]

There was a TSB back in the day for our 03's because some of the ECM connectors would let moisture in. I never had a problem but many did.

 

[Motorhead]

After a lot of head scratching and foul language, *I pulled the ecm harnesses off and found a trace of moisture. I cleaned them with an ELECTRICAL COMPONENT CLEANER looks and smells just like carb cleaner, but whatever. Did the injector harnesses too. Got everything clean and dry, applied some di-electric grease and she's running like a hound again! *
Thanks to the guidance from Jeremy at DownTime Diesel in Mesa, Az. That guy is the real deal, and a genuine good dude if you ever need work done in AZ. *

Glad you found the problem and reported back to us what you found. One little electrical glitch can cause a lot of hair pulling.