3.0 flex fuel with low power

[williamigriffith]

I recently bought an immaculate Ranger Edge with 3.0 flex fuel engine, automatic, 2WD and 120,000 miles. On hills the truck seems to be starving for fuel and cannot maintain speed. If you depress until downshift, it still cannot maintain speed and knocks a good bit at the higher RPM. The codes I am getting are misfire on 4/5/6 and lean on bank 1. Bank one of course should be opposite from the misfire side. If I reset the codes, they won't return until the engine is pulling on a hill, particularly above 50 mph. It starts easily and idles a bit roughly, but not terribly. I think it does better when it is cold, but not sure. These symptoms are overall better due to a variety of maintenance that I have performed (the female owner changed oil religiously, but little else), which includes: new plugs and wires, new air filter, cleaned MAF, cleaned Throttle Plate (for idle), replaced fuel filter. Unfortunately, it still lacks power and seems to be starved when asked to work. I ran some Techron throurgh it, but that made no difference. I also tried some E85 to no avail. My code reader is not real sophisticated, so I am not sure if there are any other codes that it may not be telling me (I doubt there is, but??). I was considering looking at the EGR differential pressure gadget, as I thought that could possibly be causing some of this. Also, I have not looked for vacuum leaks, but I was thinking that such a leak might make it idle rough, but problably not lean out, unless it was a huge leak or causing some other malfunction. I don't think the coil pack is involved, because I switched a few wires (fires on compression and exhaust stroke) to no avail.

If I thought the local dealer was good, and they aren't, I would take it to them. Does anyone have any plausible explanations and/or remedies?

Griff

 

[TomB1269]

O2 sensors been replaced? And have you tried Seafoam to clean out the carbon? And FYI, the trucks are under powered particularly if you have a 3.55 rearend hils are going to drag it down.

 

[SixFoFalcon]

Looks like you are on the right track with the maintenance you have done so far.

A replacement DPFE was cheap for my '99 so I just swapped in a new one while doing some other preventive maintenance. I also did an ignition tune-up (plugs & wires), upgraded the coil pack (Accel aftermarket/performance coil), did the hot water bypass (eliminating the coolant loop through the throttle body) and Seafoamed the engine. It's hard to say that any of those things made much of a difference but at least I eliminated some variables.

Once I swapped to a 180° thermostat I never heard the engine ping again. Still warms up quickly and provides plenty of heat in winter--I'd recommend the 180° without reservation.

In your case I would be looking at O2 sensors, since you are getting a lean code for one bank and misfires on the other bank. Could be that the bank that is prone to misfiring under load has been running rich for some time leading to excessive carbon buildup.

One more thing--as a general rule, anyone with a Ranger should inspect the throttle cable for excessive slack. I needed to take up about 3/4" of slack in my cable (@98k miles) to be able to get full-throttle when I pushed the pedal all the way down.

 

[williamigriffith]

More questions

Thanks to both responders.

I have not done anything with O2 sensors, I believe there is one upstream and one downstream of the catalyst on each bank. It seems extreme to replace them based on the possibility of their being implicated, unless they were real inexpensive, which I suspect they are not. Is there a reasonable way to test them? I know they are supposed to deliver a voltage to the PCM that is related to oxygen level in the exhaust, and little more.

When I get everything working, I will try the 180 deg. t'stat, but right now that is not the main problem.

As far as Seafoam goes, I know they make engine and trans products, but I'm not familiar with the product you were suggesting. Which one is it, and are there potential side effects?

I suspect I don't have a frisky rear end ratio, but the power problem of which I speak goes well beyond that. No one would buy a new truck with the performance of this one.

Griff

 

[SixFoFalcon]

Typically your "too lean" code means one of two things: Either that bank really is running too lean (unmetered air from a vacuum leak, insufficient fuel, etc.) or it's not running too lean but the upstream O2 sensor is spitting out values that make the PCM think it's too lean. In the latter case, replacing the O2 sensor does the trick. In the former, you are obviously going to do some more troubleshooting.

You don't need to worry about downstream O2 sensors as they merely monitor the catalytic converters to make sure they are working properly.

The Seafoam I'm referring to is the regular non-aerosol solvent. Colloquially, "Seafoaming" your engine consists of using a vacuum line (typically the brake booster vacuum line) to deliver the solvent to the intake tract while the engine is running. The solvent action and the flash-vaporization of the liquid breaks down carbon, varnish, etc. from the combustion chambers, and to a lesser extent, the lower intake tract.

How did your old plugs look when you changed them?

 

[williamigriffith]

More Ranger 3.0 flex stuff

The plugs were actually changed by the seller's mechanic several days before I bought it, and the seller said that it had been fixed a misfire 4 code. Apparently they reset the code and nothing was lit when I picked it up, but there were remaining issues that I am now addressing. The seller struck me as being very straight forward and honest, but I will check that they were actually replaced (she said they installed the autolite double platinum O.E. plugs). The rest of the things I listed, I did myself.

I never mentioned that it was a 2003 model year, I imagine the flex engines have not changed so much.

Today I reset the misfire 4/5/6 and Lean bank 1 codes that have recently cropped up and drove it around town without event. It seemed pretty normal, it is primarily when you are trying to maintain higher speeds on a grade or going up steep hills that the codes are generated.

I would think that if the O2 sensor was sending an errant lean signal the PCM would adjust to enrich, and that the lean operation that I perceive would not be ocurring. Perhaps it does not work that way.

Is there a downside to "seafoaming"? Do you let it suck as much as it wants, or let it sip a little then put your finger over the tube? I looked at a Seafoam can and they only talked about using it in the crankcase or adding it to the fuel in the tank.

Griff

 

[chiloh30]

I know i am fairly new here but your problem sounds like one I was haveing with my "99 3.0 flex fuel.
I found that i was sold the wrong plugs with it they were what we used to call 'cold' plugs.
Got to reading on what it should have in it and they were a much "hotter" PP (platinum plus) plug, switched all of my plugs over to these and change all three O2 sensors and never had anymore prob,,this worked for me