It can have a coil failure and give you a low grade missfire that only shows up when the engine has a load on it. Both times I've have this happen thats the way it started out. When it happened to my truck I had brand new coils one week old. Went through a huge puddle water got all up in there and wiped out #8. Happened to my van on a rainy day with a coil set that was 3 years old with 50k on them. I bet its a coil. Theyll still fire. Just not all the time and its much worse under a load.

 

How wet did the engine get? If water got to all 8 and they wernt greased enough yeah I think it could cause major issues like that.

 

Just skimmed over...

Most likely, you have an intermittent electrical connection in the portion of the circuit that provide switched battery voltage to all 8 COPs.

Another idea is that one of the RFI caps may be intermittently shorting or leaking internally. This might cause a momentary sag in the supply voltage but the current draw isn't enough to blow the fuse. A possibility but I wouldn't consider it very probable.

Steve

 

Well you bring up a valuable point. Before this all started after the roush charger install I did pressure wash the engine. I guess I should pull the coils and check. I do wash the truck 2-3 times a week making sure to get the inner wheel wells clean in the front, possibly spraying water on top of the motor. Thank you for info. Has anyone seen pcm replacement for this problem? I hope not cause the pcm is 700 and then a massive reprogram $$$$$ roush!! Thank you

 

RFI caps meaning noise resistors? Ihave thought about a bad connection at connector 139, rh engine compartment next to computer, power wire from fuse box to coil packs. Controls all eight coil packs with the positive wire right from the fuse box. thanks

 

PCM replacement for this problem? Seemed like a common thing for escapes, did a search, 75% of time pcm replaced.

 

I just completed a Roushcharger install in November and have been having a similar problem. My truck has only set DTC P0358 three times. The last this morning under load. It has also set P0357 & P0352 but only once.

At first I suspected I damaged the wiring harness during the install mods, but no way on both banks.

A few weeks back I changed COP #8. But since it threw P0358 this morning, I am suspecting that the nickel anti-seize I put on the plugs is causing the problem -- if that is even possible?

Plan to pull plug #8 once the engine cools.