Stumped: Ongoing Miss In '96 E-150

[Tenneire]

We have a '96 E-150 Clubwagon. A few weeks ago it developed a miss that eventually shut it down. Pulled the tank, and found a bad connector so we fixed the connector. Jump ahead 2 weeks, the pump goes dead. So this weekend we put in a new fuel pump. Pressures up, plenty of fuel, good spark. Van ran fine all day Sunday, ran fine this morning.

This evening went to start it and is developed a ragged miss at idle, then missed all through the driving range. Came home, parked it. When out a couple hours later, turned it over: Idled fine, but a touch high; put in reverse, missed for a moment or two, then smoothed out; Took it up the road, drove just fine till it hit 45+ then it started missing. Not a dead miss, not enough to really choke it, just a ragged miss.

The ECC isn't throwing any codes. Any clues?

 

[flareside_thunder]

How long since you've done a tuneup? Make sure all the plug wires and associated wiring harness connectors are clean and tight. Pull the distributor cap and check for carbon tracking on it. What engine does the van have? If it's an 8 cylinder, make sure 2&4 and 7&8 plugs wires aren't touching and are routed away from each other.

 

[Tenneire]

New distributor cap put on it before Christmas '011. It's the 5.8 8cyl engine.

The last ECC codes we pulled was when it shut down the first time and one was for low-fuel pressure and the other was for a misfire condition. But it never threw either code again after we fixed the pump wiring connector.

 

[flareside_thunder]

Still, check the cap. Have you attempted pulling the codes within the last day or so? Kinda pissing in the wind without any..... Have your TFI module tested at the parts store, check your coil for any cracks or damage and sparkplugs as well. If you haven't done a full tuneup recently ( like the last 30k miles) then I would go ahead and do that. What is the RPM the van idles at when in park and in gear? If you have a multimeter, look up how to check/adjust your TPS. That's all I can think of this late.

 

[Tenneire]

- Checked the coil before we replaced the pump
- Ditto the TFI module.
- plugs and wires we haven't checked yet.
- RPM, no clue as we don't have a gauge for it.
- Checking the TPS with a meter is something I hadn't thought of.

It's not showing any codes, hasn't since the first time we fixed the pump. Which was what I found odd, cause it didn't toss any code when the pump failed.

 

[Ton van der Sluijs]

How long since you've done a tuneup? Make sure all the plug wires and associated wiring harness connectors are clean and tight. Pull the distributor cap and check for carbon tracking on it. What engine does the van have? If it's an 8 cylinder, make sure 2&4 and 7&8 plugs wires aren't touching and are routed away from each other.

Thank you for this info

Ton

 

[Dukes78]

You said it had plenty of fuel. Have you checked the fuel pressure? Most injection systems need specific amount of fuel pressure to run correctly. Usually its between like 50 to 60 psi if they have to little they will starve on fuel and to much will cause the fuel return to rob some of the fuel the injectors are needing not allowing enough fuel to the injectors. Also have you replaced the fuel filter?