Something I just thought about. If #4 and #6 electrical plugs that connect that connect to the packs are reversed, will the ecu notice this and adjust?

 

i really dont know. i dont think so. i think you would just get misfires in 2 cylinders. i guess from here check your injector at cylinder 4 and go from there.

 

Yes that was just a thought. I was not sure if these ecu's have any advanced programming or its all just basic routines. I am not thinking it does since it can't detect an a loss of connection and only a misfire. Computers in cars are so far behind. I am thinking what I thought originally is probably the culprit which is a bad injector. Seeing I had switched the packs too it is either the injector or a bad ground. I am not sure where the ground is. I have a image from a full harness and it looks like it would be in the front of the block somewhere. But in any case I will go through the connections and make sure there are no connection issues on the plugs ect.

 

I know it sounds like snake oil, but I installed Seans ground kit and fixed a lot of small issues. Check all of your ground points and clean them. Just doing that alone solved a ton of issues in my old Porsche, and 1985 had a ton less computing power than this 2003.


if you want to buy a set of stock injectors to send out and not have downtime, PM me. I had mine rebuilt with a flow chart and it cost $120 plus shipping, and I bought a spare set to send for $90.

 

Hey I will keep that in mind. I think it is a grounding issue. One of the bolts was loose on those grounding wires. It was enough not to make a rattle but they could move around behind the nut. This may or may not have been the problem but I had no issues today. I will keep a close eye on everything for now.

 

ya seriously you should check out SxExCx grounding kit. i have one and dont regret the decision. if you live in socal he will even install it for you at his house. really cool guy.

 

Oh yes, I will be looking into that in the near future.

 

Just wanted to post an update. A couple days ago the car started up with the same behavior as in original post. Except now it was also doing it after shutting down for a few mins then starting back up. Ended up being a bad injector which I am replacing it tomorrow with a spare a friend has. It is probably just dirty and will see if we can clean it out or if it needs to be rebuilt. But in any case thanks for the help!

 

Did not replace the injector yet. Was talking with one of the techs at the dealership and told me to try out BG 44K fuel system cleaner before replacing the injector. He told me it may fix the problem and sounded like what I think it is, injector sticking open. So I decided to go ahead and try it out. It seems to be doing well and not had any problems yet.He said it should increase the fuel economy of the car too.

 

Good luck.

 

I found the problem and I feel like an idiot. Yesterday when I replaced the intake manifold I replaced the injector for #4 as the cleaner did not work, but the car has ran smoother since I used it (2 fill ups ago). It ran fine last night, but this morning it was back to the same problems. When I was checking the connections of the #4 coil pack I hit the #6 with my hand and it jiggled. I thought the pack may have broke but it was just not secured down. I bolted it back down and started the car up, it ran fine. I even unplugged the pack to see if it ran like before and gave the same code. It did. I am not sure how I did not notice this before, but nonetheless that was the problem and explains the randomness of the misfires.

Not sure why the ecu is showing a #4 when it is actually #6 misfire. I check the wires and the red/grey wire is on the plug to #6 and it is also the middle plug. #4 is connected with the plug at the firewall side. So I am lost there, but I am happy that is what the problem was.




Note: for some odd reason half of my text I typed disappeared, when I hit submit.