Rough idle when wet outside
#11
Senior Member
Originally Posted by 06F150CFCT
ToughFX4, you had to be right. This is what my old fuel pump driver module looked like when I took it off and wire brushed it:
Huge hole on the back and corroded all over.
Here's the new one on the left and old one on the right.
After I took it out for a drive it didnt hesitate at all when accelerating in the high rpms like it did before. When it rains out next I'll have the real test but I am certain that was my problem. Again, ToughFX4 thanks for pointing this out as it has saved me many more countless headaches trying to figure out what the problem would have been.
Huge hole on the back and corroded all over.
Here's the new one on the left and old one on the right.
After I took it out for a drive it didnt hesitate at all when accelerating in the high rpms like it did before. When it rains out next I'll have the real test but I am certain that was my problem. Again, ToughFX4 thanks for pointing this out as it has saved me many more countless headaches trying to figure out what the problem would have been.
#12
I have similar symptoms as 06f150cfct and wanted to chime in ask if this did in fact fix the original issue you were having.
my 04f150 4.6l can run flawlessly for weeks and then I started noticing occasionally it would run rough and shake when accelerating. For the longest time I didn't see the pattern until here recently. It all seemed to be happening during /after rainy or snowy weather. We had such a dry summer last year that I almost forgot about my issue.
Anyways, my truck would throw up codes most of the time during this issue, however all the codes always seemed to be specific cylinder misfires. So I spent lots of time and money replacing the plug, COP, then the injector then the problem would shift cylinders. Rinse and repeat (even on the same cylinders).
I ordered a new fuel pump driver module from amazon today and it should be here in two days. I will replace it and report back after that.
I did manage to snap a few (bad) pictures of the module under the truck. Can't really tell yet without taking the module off how bad it is though.
my 04f150 4.6l can run flawlessly for weeks and then I started noticing occasionally it would run rough and shake when accelerating. For the longest time I didn't see the pattern until here recently. It all seemed to be happening during /after rainy or snowy weather. We had such a dry summer last year that I almost forgot about my issue.
Anyways, my truck would throw up codes most of the time during this issue, however all the codes always seemed to be specific cylinder misfires. So I spent lots of time and money replacing the plug, COP, then the injector then the problem would shift cylinders. Rinse and repeat (even on the same cylinders).
I ordered a new fuel pump driver module from amazon today and it should be here in two days. I will replace it and report back after that.
I did manage to snap a few (bad) pictures of the module under the truck. Can't really tell yet without taking the module off how bad it is though.
Last edited by Derek Pinkston; 03-08-2013 at 11:03 AM.
#13
I'm having the same problem where I get rough idle when it is raining and it sometimes feels like I'm going to stall out when I come to a stop.
I live in SoCal and it's raining again and I'm having the same symptoms. Last weekend I pulled the FPDM and the corrosion looks really minor. I didn't take it all the way off but as far as I can tell it is just on the surface. Could the FPDM still be my problem? It's not that expensive but I don't want to just throw parts at it either?
I live in SoCal and it's raining again and I'm having the same symptoms. Last weekend I pulled the FPDM and the corrosion looks really minor. I didn't take it all the way off but as far as I can tell it is just on the surface. Could the FPDM still be my problem? It's not that expensive but I don't want to just throw parts at it either?
#14
That doesn't look that bad. Mine looked a little worse, I replaced it and I'm still have similar issues (usually on or after wet days).
I'm starting to wonder if it's a problem with moisture getting down in the plug wells or something.
I'm starting to wonder if it's a problem with moisture getting down in the plug wells or something.
#15
Yeah that was my original suspicion. I know that I'm almost up to replace all my plugs anyway. Maybe I should just do that. I just hate throwing money at a situation not knowing if it will actually fix the problem.
#16
Senior Member
I replaced my fpdm but have the same problem that you do I can't figure it out. I personally just thought it was me thinking things but it's good to know it's not just me
#17
Senior Member
If you're "almost up to replace" the plugs, then just replace them. Especially if you have a 5.4, the sooner the better. However, the plugs are going to fix your issue. Replacing the boots might though. Clean the corrosion off of the contact point on the coils. Use dialectric grease between the coil/boot spring, and the boot spring/plug. That way your not getting moisture in those connections. If that doesn't fix your issue, then start going over every connector that's open to the elements. Make sure they're clean, tight and as water proof as possible.
#18
If you're "almost up to replace" the plugs, then just replace them. Especially if you have a 5.4, the sooner the better. However, the plugs are going to fix your issue. Replacing the boots might though. Clean the corrosion off of the contact point on the coils. Use dialectric grease between the coil/boot spring, and the boot spring/plug. That way your not getting moisture in those connections. If that doesn't fix your issue, then start going over every connector that's open to the elements. Make sure they're clean, tight and as water proof as possible.
#19
Senior Member