4.0 Bad miss in overdrive and drive at low rpms

[sward1979]

I have done everything I know of. I have replaced the coil, wires, plugs etc. I have done that more than once. I done a compression check and found that one head was cracked so I replaced both. That brought the compression up. I have had the injectors checked and replaced the fuel filter. I have replaced the computer, ignition module, crankshaft sensor. I took it to the transmission shop thought it might be there but they said everything is fine there. It never trips the check engine light so I can't even get a code. Any help would be great.

 

[fireguy12117]

have you investigated any of the wiring of the truck? made sure all the grounds throughout the engine bay were good, clean and tight? made sure there were no obvious signs of damage to wiring harnesses? wiggle tested as much of the harness as you can get at?

i had a '93 4.0 with a horribly corroded engine wiring harness right behind the power steering pump where the harness crossed from the block to the wheel well. 80-90% of the wires were corroded with broken insulation when when i romoved it 50% of those just broke right in half. the engine ran right up till i shut 'er off and started pulling things apart. i later found the bad harness after the motor was pulled.

 

[sward1979]

Thanks that was going to be my next step. Its hard to believe but this truck only has 73,000 on it. This thing looks like brand new. Would make a very nice truck if I can get this problems sorted out.

 

[97ranger4x4]

Yeh, well it may be worth it to spend 100 bucks at the dealership to have it diagnosed. I had to do that with my truck last week. One of my fuel injectors (that I replaced 3 months ago) went bad. The OHM resistance is supposed to be between 11-18 ohms, mine was 5. I put a new one in, and it purrs like a cat!

 

[brock71]

Ignition miss intermittant

I have a 2001. Three times in the last 10K mi I have experienced what I think must be a miss at highway speed. Feels like igntion stops for a brief second then comes right back. The drive line clunks and I feel like I must have run over a sharp bump in the road.
The check engine light does not come on. The tach does not dip. I was looking right at it when it happened once.
IS it possible I have codes stored even if the check engine light is off?

 

[vaderj]

The check engine light is lit by a light bulb and god knows the bulbs behind the dash die; I had a zx2 escort that had the CEL die (after about 5 years of being on); any of the parts stores should be able to loan a code reader for a quick check

 

[Earl43P]

sward1979, Does it have an EGR?

If so, drive it with the vaccum line to the EGR valve taken off and plugged. I've seen EGR problems arise at light throttle, steady speeds.



Brock71, you may want to start a new thread. An 01 has little in common with a '90, and your problem sounds quite different.