I have an 1997 E350 5.4 that started with a Misfire with no codes.

1. Brought it to Ford: They replace all sprk plugs & coils: No Change they keeped Van for more Diagnostics.

2. They called me saying the O2 Sensors are bad: They replaced them: Still misfiring. 1 week already & $1100 later Van still there.

3. Called me three days later saying bad wiring harness: Replaced: No Change van still there now at $1600.

4. They check the commpression: Checkout OK. Now $1749. Van Still there

5. Called me saying bad EGR Valve: Replaced. No Change $1900. They told me to take it an put a few miles on it. No power, poor fuel mil.

6. Brought it back after about 100 miles. theve had it for another week now and tested MAF & IAC $2150 later they tell they cant find out whats wrong with it and gave it back to me.

7. Called me two days later saying a bad PCM. I returned the van for replacement add another $695 now total $2845: Not fixed.

I need some Desperate help! Thank you in advance.

 

Why did you take it to a Dealership anyway with a van 10yrs old, I've only taken my 97 expy to Ford twice in the past 3 yrs once for an oil change and for an immediate repair I wanted done on Saturday to change a wheel hub/bearing. Anyways enough preaching have you ever changed the fuel filter, and I would also try a fuel system cleaning. Oohh crap I almost forgot also check all your vacuum lines and change your pcv valve. Hope one these helps.

 

I did check the PCV Valve. I didn't find any vacuum leaks. I brought it to ford only after I couldn't figure it out on my own. I put a noid light on it and it flashes for about 30 sec. then goes out runs rough. I took off the Catalytic Converter to see if it bad. Running without the Cat right now. Some mention to me to buy Auto Tap it suppose to be better. I don't know what else to try.

 

Besides the noise, How does she run without the cats better?

 

If I didn't have the Misfire it would be good.

 

Now this is just a toss up maybe a bad or clogged fuel injector? Besides that I have no other suggestions for you except to back-track. I would especially double check the spark plugs and coils to see if the plugs are snug and coil connections are OK. Post when you get her running again. Good luck.

 

I had the same problem on a 97 F-150.
Checked everything but couldn't find the problem. Changed plugs, wires and coils. Still had the miss. After about two weeks of searching it only took a tube of dielectric silicone to fix the problem. I just put some inside each ignition wire before I pushed them back on the plugs and I have never had a miss since.
Before I used the silicone I must have removed and re-installed the plug wires a dozen times. Each time I thought I had them on right. I even heard the pop sound when the wire connects to the top of the spark plugs but I guess they never really made a good connection.
This tube really fixed the problem. I always use it now.

I hope this helps.

 

The 5.4L doesn't have wires, but it should be installed on the coil boots. If you are losing the signal to fire injectors, then perhaps it is a bad crank/cam sensor or cylinder head temp sensor causing it to go into safe mode by shutting down every other cylinder to try to cool the engine (even though it isn't actually hot)

 

I'd be standing ON a service manager's desk long before now discussing his "parts hanger" in the service bay. There is no excuse for a dealership to not have a trained tech who can efficiently diagnose a misfire instead of charging a customer for all his failures and experiments.

Time to press for a refund and to find a new technician.

Steve

 

I agree I would be so far up the service managers rear I would be able to give him a cleen bill of health. personally I would have never let them keep guessing and parts changing. If all these parts they keep changing arn't fixing the problem put the old stuff back on and give you a refund. And take it somewhere else.

 

The F-150 I worked on had a 4.6 and was change to a 5.4. That's why it had ignition wires.
Sorry for not making that ckear.

 

I agree they have VERY expensive diagnostics machines that should measure the resistance on every single component on that engine and they should find the problem within a few hours at the most. Sounds like they gave it to the oil "tech" and he had fun in the parts department. If no sensors or ignition components test bad I'd think they would do a compression and leak down test and go from there.

 

Just curious.

Is the misfire only a idle?
Under acceleration?
Under Hard acceleration?
When coming to a stop?
All the time?

I had a miss during idle on my 97 5.4 Expedition. The dealer could never find anything, and I wouldn't authorize shotgun troubleshooting with my debit card (replacing all ignition parts, etc, at one time). No Check engine light, etc.

I was always looking under the hood at vacuum lines, plugs, etc. At one time, I got a lean code C.E.L., and replaced all 4 O2 sensors, at around 120,000 miles.

I went through all the iginition parts and replaced plugs, checked coils, etc. Finally, I pulled the fuel rails off and checked each injector. I found a cracked injector hat, coincidentally, it was on the same cylinder that had a plug that was routinely discolored from the other 7.

I replaced the injector, and haven't had the problem return. That was about 3 years ago or more.

In the process, I did find cracked vacuum lines and PCV lines, but those didn't seem to correct the original problem of missing.

Recently (8 months ago), I did have the EGR code (401?) and found a broken vacuum line behind the battery

I hope it helps.

Vincent

 

Misfiring all the time. I did swap out all the 02 Sensors and it seems to be run smooth but when driving at about 2500 - 3000 RPM's it has a really bad vibration.

 

With the truck in N or Park, if you bring the RPM's up from idle, does it start to miss at a certain RPM? Does it run fine in N or Park, but when placed in gear and running under a load start to miss?

You are having the problem I feared. Ford's #1 service tech is troubleshooting with your Mastercard or Visa.

Besides what the Ford Service Department has replaced, what have you done as well?

Vincent