I will dry to make this as brief as possible.

I have a 2000 Excursion, 4WD, v10, with 115000 miles.

After some very heavy rains this past January and February ( rare for southern California), I went out to start it and it felt and sounded like it was running on 5 cylinders, and the check engine light was on ("Service Engine Soon" light). I let it run for a bit hoping it would clear itself out.

I limped it over to the closest Ford to to have them check it out. I told them I thought it might be plugs or coils. They are 23 years old.

They checked it out and called me to say they thought the main problem was the PCM. One whole bank of coils weren't getting signal. After they replaced that, they then said it was running much better but it did look like it could use the plugs and coils. So they replaced them too. When I went to pick it up, low and behold the check engine light was on. I thought maybe it just had to be run a while and driving it home might clear it all out. No. Light stayed on. I disconnected the battery to clear any codes, but didn't solver it.

Searching on the web I kept running across O2 Sensor suggestions. So I replaced both sensors before the converter. It was not an original California vehicle so it didn't have the 2 behind the converter. That seemed to fix the light issue for about 4 days, and the light came back on. I called the tech that worked on it and he came over with his computer and he said he had never seen the code that came up. Said it was some kind of grounding issue. He was going to call Ford and see what it meant. They told him to look into the relay that that connects to the PCM might be causing it. Well, they replaced that and the light was out. He drove it for a few miles and all seemed good. Until the next morning when he started it up and the light was back on. Now he wants to replaces the ignition switch?

Can anybody here guide me as to what might be wrong? What to look for? This whole process as been going on since March 3. Over six months. HELP!!

Sorry this long. I wanted to give you all the info to help find a solution. Any suggestions or info appreciated.

Thank you all.

Charlie

 

There are times when a code is not very specific and a lot is up to the tech to examine the suggested areas the code suggests. Codes don't tell you which part is defective , they only provide some direction. It all depends on what the tech thinks and knows about the area the code directed them to.
Some problems can be elusive and try a tech's patience and knowledge., but this is where persistence pays..
Intermittent problems are a tech's worst nightmare..
Would you by any chance recall what codes were coming up ?

We have all been there at one time or another and there are times we wonder what did we overlook.

 

hanky,

Thanks for the reply.

The code we are getting is P1630. Any ideas?

Thanks

 

Since you paid for the repair and it still has the same problem, I would take it back to Ford and have them find out what is really going on.

The code suggests a problem involving the PCM, which was supposed replaced. This could take some time to pin down and both you and the tech have to utilize some patience to find the cause.
We know what the result is ,PCM problem, but now the cause needs to be found and sometimes it is easy and other times it can try a tech's patience and determination.

The electronics in the vehicle operate at some very low voltages and those low voltages can be greatly affected by the slightest resistance possibly from a poor connection
SOME PLACE and they are many.
Hopefully this will provide some idea of why it can take so long to find some problem causes.