Some issues

[r0llinlacss]

1998 EB 5.4 w/ 249,000. Dealing with an intermittent misfire and stalling. Some times it will restart and other times it won't. The spot where it's sitting now, it will restart every time, but if I go drive it, it won't restart. It hard to start on a cold start, and there is shaking/hesitation under heavy throttle, but not under light throttle. Sometimes it wants to stall out from pressing the gas even the tiniest bit.

The time it died when I drove it, and wouldn't restart, I checked fuel and there was good pressure, and there was spark but no start.

I've replaced two coils, the fuel pump, fixed a vacuum leak, and cleaned the MAF.

The person before me replaced the EGR, all of the plugs, fuel filter, and fixed other vacuum leaks.

I took a couple videos today to make it easier for you guys to see what it's doing.


Here is a cold start and warm up:
https://www.youtube.com/watch?v=0MPJy4Fm2y4&feature=youtu.be

Here, I almost got it to stall a couple times. It did stall right before I started recording.
https://www.youtube.com/watch?v=9bUDRfx2nQI


Watch the videos and tell me what you think.

 

[docraymund]

First of all have codes read, take out all spark plugs and examine them, check fuel pressure with a gauge and check for vacuum leaks. Hopefully you will find the problem. Good luck!

 

[stamp11127]

Troubleshooting this problem started in the following thread:

http://www.expeditionforum.com/f16/98-expedition-multiple-problems-29291/

Since you stated there is a new egr valve, have you tested it's operation? Have you looked at the egr ports to see how clogged they are?
If your scanner will show live data, look at the front O2 sensors voltage reading. I don't remember what level indicates lean or rich but that would tell you if you have a vac leak on the intake side.
With today's vehicles even though parts "look good" they may not be. That is why we go with facts from our tools and why we ask for specific values. It is better to prove failure prior to condemning parts. Otherwise you just end up tossing parts at the problem. The fuel filter may be restricted but look good on the outside.

So again, what is the fuel pressure when it dies? If it dies with 34 lbs of pressure then you have proven it is not fuel related.

Sounds like you may have leaks on the exhaust also.

 

[r0llinlacss]

Thank you moderator for closing the old thread, I wanted to move it anyways since I figured the electrical part out.

I neglected to mention I've checked spark on every cylinder and unplugged every injector, they all sparked and all make a difference in how it runs, so that should mean the new plugs are sparking as they should, correct? Also checked injectors with test nodes and they all pulse as they should.

I also sprayed all around the intake and vacuum lines with carb cleaner and found no difference there either, so I assume there are no more vacuum leaks and no intake leaks.

I have not tested the EGR valve. I've read other threads about ports clogging on the throttle body, should I check there as well?

My friend can't find his fuel pressure gauge so I can't test that at the moment.

And yes, there is a small exhaust leak somewhere. The guy before me disconnected the exhaust to make sure the cats weren't clogged and I don't think he got it back together the best. Not the greatest way to check for clogged cats either but whatever works I guess.

Also, still not throwing any codes.

 

[Al95]

The idle air control something like that. My truck did the same thing stalling had to give some gas to stay on then on gear shift it would stall and turn off.

 

[r0llinlacss]

Alright, more progress today.

Turns out the EGR is not new, but the IAC is. I was told the EGR was new but it's the IAC after closer inspection.

It died a lot today and eventually wouldn't start at all. Checked spark and injector pulse and it had both. Checked fuel pressure and there was none, but the fuel pump still kicked on. So, it turned out the gas gauge doesn't read right and it was low on gas. I added about 10 gallons along with some HEAT and fuel injector cleaner. I was told it sat for a long time before previous owner bought it so I added the HEAT and injector cleaner to be safe.

After adding gas it started right up and hasn't died since. I drove it a few places and it rides well.

But there is still an intermittent misfire at idle, and lots of throttle makes it worse. Accelerates smooth with about 1/4 throttle but anything more causes shaking/misfire.

 

[docraymund]

Best bet: change the fuel filter. It might be clogged.