I'm having an intermittent issue with injector #4 throwing a P0204 code which eventually triggers a P0304. I put a noid light on it during the issue and it indicated wide open throttle while the engine was idling. Then the injector will simply go back to normal operation without any changes. Driving down the highway I can smell it dumping fuel during the malfunction. Take it up to wide open throttle and the engine runs normally. Just super fat during low throttle and intermittently.


Couple background details. I've only owned the car a few months and it has 111000 miles. 06 Jun-02 production date. Ford replaced the engine October 2007 at 53308 miles after loss of oil pressure wiped out the rod bearings. Engine assembly was 3W3Z-6006-ABRM. which I think tells me it was a long block and they reused the intake.


Also not sure if related, but the speedometer needle will occasionally and randomly drop/fluctuate and then return to normal operation. The two have not coincided and the speedo issue is much more rare.


Has anyone experienced this before? Thinking maybe mechanic damaged the wiring harness when they replaced the engine. Looking for some input before I start cutting the harness apart to find a chafed wire.


My understanding is that the injector fires when the computer grounds the circuit. If so, I'm thinking that an intermittent ground short could cause the issue. Problem is I haven't found it by moving and wiggling the harness.


Thanks in advance.