Idle issues/warm engine issues <SOLVED>

[Cole94]

94 explorer 4.0 pushrod engine

For some time, the engine has had a rough idle issue starting warm, and the other day it died going down the road.
Now it's rough idle COLD AND WARM and lack of power going down the road ONLY WHEN WARM. It's fine driving cold, but when it warms up, it's like hitting a wall and it bogs down and I can't go any faster than 35mph.

I'm stumped. What I have done:

• Egr valve replaced
• Egr tube replaced
• DPFE sensor replaced
• Spark plugs replaced
• Plug wires replaced
• Ignition coil replaced
• Checked the cats (clean)
• Fuel filter replaced
• Fuel pump replaced
• Checked fuel pressure (30psi idle)

No change.
No CEL, it flashed on for 5 seconds going down the road and went back out again...

Anyone got ideas? Cleaning the MAF next...

 

[massacre]

IMHO clean MAF and check for vac leaks?

 

[Cole94]

yeah, we checked for vac leaks, and I thought we found them all. Any ideas for checking for leaks other than carb/choke cleaner?

 

[massacre]

yeah, we checked for vac leaks, and I thought we found them all. Any ideas for checking for leaks other than carb/choke cleaner?

Only other safe way I know is with a smoke machine

 

[Cole94]

Only other safe way I know is with a smoke machine

ahhhh... well don't have one of those, but I have some really smokey incense... maybe that will work... I'll post back with the result as I get to them.

 

[massacre]

ahhhh... well don't have one of those, but I have some really smokey incense... maybe that will work... I'll post back with the result as I get to them.

10-4 good luck

 

[Cole94]

Alright, so the update from last night...

no vacuum leaks... at least as far as I can tell from incense.

Haven't cleaned the MAF yet, but unplugged it, and idle smoothed SOME, not completely.
Same with TPS. except TPS makes idle go up slightly, and I believe that is the reason for the smooth out.
And IAC, engine almost stalled, soooo not that.

Cleaning the MAF tonight, as well as replacing the fuel pump assembly. found a crack in one of the metal nozzles coming out the top, enough to squirt, but I don't think its enough for pressure loss.

Cleaning MAF tonight will reply with results...

 

[Centaurious]

You could always try reading the codes, most errors don't cause a constant light.

Ford OBD/OBD2 Codes – TroubleCodes.net

 

[Cole94]

I did, got a 543: Secondary Fuel circuit open

Ignoring the code, could it be bad fuel?

 

[Cole94]

Thanks for all the help guys... but I got the problem solved.

In a last-ditch attempt to fix it, me and my dad went and got a fresh tank of fuel and put a bottle of HEET in it, but I got 50 miles in 10 gallons and it was getting hard to start.
Finally got fed up with it and dad sent it to the dealership... they hooked up their expensive computer and couldn't find ANYTHING... not even a code. They tested the fuel... sure enough, the octane level was "too low to even run a lawnmower," and the fuel was gelled (below freezing temps night before). Guess it was water in the fuel after all... They are draining the tank, cleaning it, and putting a new fuel filter on.

I hope this can help someone else down the road.​

 

[massacre]

That’s great that you got it sorted out! That’s a rough one to diagnose but looks like the heet was pointing you in the right direction