Runs rough, like it has a miss

[the4biddendonut]

I have yet another problem with my SHO. I thought I had a miss in one of my cylinders, so I performed a tune up because it needed one anyway. It ran fine for a day, then all of a sudden it started running roughly again like it did before the tune up. It idles rough and has hardly has any power.

Has anyone run into this before or have any idea what could be causing this?

 

[Eric VerValin]

You really should run the codes, that'll give you direction to look. Too hard to say without knowing. And what do you define as a 'tune up' ?

 

[the4biddendonut]

I ran the codes and didn't come up with anything conclusive. 4 codes popped up, but I don't have them with me. From memory, 2 of them said that the temp was out of range, one said something about the tach, and the last one was for the fuel pump relay.

 

[the4biddendonut]

I finally traced it down to a bad connection to the primary side of the ignition coil. I'm going to clean up the pins and see if that doesn't fix the problem, thanks for taking a look. I'll post again with what I come up with.

 

[Eric VerValin]

Well the 2 temp outta range could be from it not being warm enough when you ran the test, and I wouldnt worry about that much. But the fuel pump circuit can mean your fuel pump isn't putting out enough pressure. And yea, anything like that can't hurt. I cleaned up all of mine, put a little dielectric grease on em, and called it done. I'm assuming you have new cables and plugs?

 

[the4biddendonut]

I found that the primary connection to the coil and the pigtail on my engine harness were different for some reason. So that was causing a bad connection. I found a new pigtail from the local ford dealer for $22. It's expensive, but it's either that or buy a new coil. I soldered in the new pigtail and it runs beautifully now.

 

[sho'd]

I found that the primary connection to the coil and the pigtail on my engine harness were different for some reason. So that was causing a bad connection. I found a new pigtail from the local ford dealer for $22. It's expensive, but it's either that or buy a new coil. I soldered in the new pigtail and it runs beautifully now.

i believe that there is a alignment tap, for some reason some have them in the middle and some off to the side, next time just dremel the tab off and save your money. good to hear it's up and running though.

 

[the4biddendonut]

I thought about that, but having the mismatched alignment tap and connector ruined the pigtail. It was bent all out of shape and cracked. I don't know if it would have stayed on very well even if I trimmed off the alignment tap. Getting the new pigtail insured a good connection and helps me sleep at night.

 

[naval-avi8or]

I thought about that, but having the mismatched alignment tap and connector ruined the pigtail. It was bent all out of shape and cracked. I don't know if it would have stayed on very well even if I trimmed off the alignment tap. Getting the new pigtail insured a good connection and helps me sleep at night.

The ignition code caused your fuel pump relay code. The fuel system is designed only to operate with a ignition signal when you lose the ignition signal the computer shuts down the fuel circuit causing the fuel pump relay code. If the coil connector isn't the cause of your ignition failure than the CPS may be going bad.

 

[sho'd]

I thought about that, but having the mismatched alignment tap and connector ruined the pigtail. It was bent all out of shape and cracked. I don't know if it would have stayed on very well even if I trimmed off the alignment tap. Getting the new pigtail insured a good connection and helps me sleep at night.

yeah, it is always better to be safe than on the side of the road cursing at it. i see why you changed it.