i have a 99 ford ranger 4.0. It misses under a load driving down the road. no check engine has come up. i have replaced the sparkplug, wires, coil, but stilll did nothing. i did have a code come up on the computer and it was p1780. any idea's??

 

Code P1780 = Transmission Control Switch Out of Self-Test Range. Possible Causes:

- TCS circuit short or open
- Damaged TCS switch
- Damaged PCM

Regarding the misfire, checking the fuel pressure would be a good idea. Sounds like you've already replaced the relevant ignition parts.

P.S. Your Ranger wouldn't happen to be losing coolant, would it?

 

ya i think it might be loseing some. why what are you thinking?

 

Mysteriously disappearing coolant from the 4.0L OHV can mean a few things - intake or head gasket leaks, or even slightly cracked heads.

This is not to say you are looking at for sure, just something you ought to keep it in mind. You should have a UOA done and then you'll know for sure.

BTW, the Transmission Control Switch is that button at the end of the shift lever.

 

A couple of years ago I was having a misfire and it turned out to be one of the injectors. But, my check engine light came on and the code basically said a misfire in cylinder 3 I think it was. It's something to look into anyway.

 

Welcome to FTE.

How many miles on this ride????

Which plugs & wires did you use & did you test/check them for defects before installation, or do you think you may have cracked a plug insulator during installation????

Did you route the plug wires exactally as the factory had them & use ALL of the wire looms????

A misfire under load is usually spark related but that will usually set a cyl misfire code, but a miss without a code, could be injector related as had been said, or compression related, from a valve sticking or not seating well because of gum, varnish, or Combustion Chamber Deposit Flaking (CCDF), or a burned valve, or a lifter problem, or maybe sticking piston compression rings.

So if you think any of those are a possibility & you have, or can come by a scantool, maybe consider having it do a cyl balance test & see how things go.

On the cyl balance test, the scantool will disable each injector & measure the rpm drop & any cyl with a small drop is suspect, so you can go to that cyl & begin a more detailed trouble shoot, like a compression check.

Or if two adjacent cyls give a low rpm drop, suspect a gasket problem between them.

If you come to suspect a head gasket leak, you could do a cyl compression test, or do a cyl blow down test, or rempve the radiator cap when the engine is at cold idle & look for exhaust bubbles in the coolant, or maybe check the exhaust for the sweet smell of antifreeze, or as Rockledge suggested, just have a UOA done & see if comes back positive for coolant.

When the miss occurs, is there any engine noise associated with it????

How did the removed plugs read????

Edit: I suppose with the tranny code, it could be an untimely torque converter unlock & it feeling like a miss????

A whole bunch more trouble shooting thoughts for pondering, let us know what you find.

 

i have a 150,000 miles on the truck. All of the wires were double checked to make sure they were corect. I have had it on scantool and nothing appeared to wrong. All my buddies that are mechic's have looked and they have no clue along with my self. im hopefully taking it to a garage tom. to see if they could give me any other idea, or pin point the problem, so i can take care of it


and to answer paw paws question about noise when it is missing... it is not making any unsual sounds just a dead miss that u can hear and feel in the truck

 

Any updates on this issue? my dad has a 2006 2.3L with the same symptoms. no codes, plugs and wires changed. I was hoping someone figured something that i can check before I really dig into it.