Misfire problem

Hi,

Have you ever noticed gray or black smoke from the exhaust when it finally starts? Based on your description, it sounds like it is getting too much fuel. That can cause a hard/delayed start.

Also, a misfire can be caused by other things as well. For example, an engine vacuum leak can do it. Have you checked for leaks? If you haven't, here is a link that explains how to do it:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Keep in mind, low compression can also be a cause of a misfire. It sounds as though you have done a lot to the ignition system, so I suspect it is either high fuel pressure, a vacuum leak, or even low compression.

Before we go further into diagnosing, check for vacuum leaks and it would be a good idea to also confirm the fuel pressure is within spec. Here is a link showing how to test it:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Start with this and let me know the results. If you have already done this, let me know that as well. Also, if you have a scan tool that can provide live data, I need you to check two things. First, check the coolant temperature sensor signal to make sure it is accurate (best done cold so you can compare it to outside temperatures). Also, let me know what the short-term fuel trims are.

I will watch for your reply.

Take care,

Joe