Ignition/acceleration problem 2000 Explorer 5.0L

[daivddd]

I have an ignition/acceleration problem in my 2000 Explorer 5.0L. The only DTCs read are PO118 (coolant temp) and PO453 (EVAP) and I can't imagine they are the culprit. I replaced a failed MAF and it seems to be working OK. Fuel pressure remains good.

It's hard to start cold, but once warm it idles OK yet often simply dies if left idling very long. Sometimes it accelerates OK, but usually it bogs down to die unless I back off and it idles fine again. However, if I accelerate ever so gradually it speeds up.

When accelerating regularly and it bogs, I can fiddle in and out and eventually overcome the bogging and it speeds up, but if I push it too fast it coughs and chokes and backfires at the throttle body and back up to the air filter. Eventually at high RPM it again runs OK.

How can I track down what's going on?

 

[DirtDonk]

Wow, long time with no answers!
So another “back to the top“ to hopefully get things going. Or have you gotten it dealt with?

I wouldn’t rule out the coolant temp sensor issue. Somebody here probably knows how that might affect computer tuning, but if it’s afraid the temperature is too high, the computer might back way off of timing to save a struggling engine.
I’m not familiar enough to say for sure, but seems like one possibility.

 

[Bruners4]

Have you checked your fuel pressure?
Cold starts are in open loop mode and use pre-determined perimeters to get the engine to start.
I use Forscan to read my '96 Explorer ECU. Selecting the needed PIDs will help to pinpoint the possible issues. But it can not read the fuel pressure in the fuel rail.

 

[Broncobowsher]

Couple things come to mind.
Fix the coolant temp. No reason for confusing the computer any more than needed. Fail safe conditions tend to be down on power.
Next, you state fuel pressure is fine. Is that just at idle, or under load? It sounds a lot like you are running out of fuel under load.
And where did you source the replacement MAF from? There is a lot of low quality junk parts on the market right now.