2.9L & 3.0L V6 Tech General discussion of 2.9L and 3.0L V6 Ford Ranger engines.

Idles rough, barely runs

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Old 12-09-2014
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Idles rough, barely runs

Hi all. I have a 93 3.0 with about 180k. Has always had a rough idle but not too bad. Always ran pretty well, though. Now when I start it, it idles ok for about 30 sec., then idles badly. Drives VERY rough and then dies. Will restart, though. I've cleaned the MAF and idle control sensor, replaced fuel filter, checked plugs and they look perfect. I get a CEL on occasion but it goes away within a few minutes. Not running hot, oil pressure is fine, charging fine. Fuel pump seems to work fine--you can hear it come on and stop when it reaches pressure. I haven't pulled any codes because I'm afraid to drive it to the repair shop.
Any ideas?
 
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Old 12-09-2014
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Just FYI, computer has no knowledge of fuel pressure, fuel pump starts and runs for 2 seconds each time key is turned on.
When engine RPMs are above 500 fuel pump is turned on again and stays on until key is turned off or RPMs drop below 500.

No matter what they add to the outside of a gas engine they can't change the fundamentals of how they work.
The big 3 are:
spark, at the right time
Fuel, in the right amount
Compression, above 120psi

Compression usually isn't a come and go issue, so I would rule that out.
Fuel is usually RPM related, vacuum leaks, EGR, and bad injectors also don't usually come and go

Spark issue would be my guess.

3.0l Vulcan engine had a distributor and TFI ignition until 1994.
TFI was an OK system until it got older then parts and wires started to fail.

Good read here: Ford EEC-IV/TFI-IV Electronic Engine Control Troubleshooting
Print the work sheet and go thru it

Also check condition of cap and rotor
Also coil could simply be worn out.

You can read OBD codes with a test light and on a '93 I think you can get the CEL to flash the codes using a jumper wire on the diagnostic port in engine compartment
 
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Old 12-09-2014
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Ron, thanks for the quick reply and good info. I'm still a bit confused, though. My 3.0 doesn't have a traditional points, coil, condenser distributor. It is electronic. Still, it could be the wires. I replaced them a year ago in the hope that it would smooth out the idle but there was no change. I suppose that there could be an arcing issue if the wires are too close together. I can check the routing on them. I haven't checked for vacuum leaks, but as you say, the lines do become brittle over time. They're more than due for an inspection so I'll check that. What else could I check? Thanks, Bill
 
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Old 12-10-2014
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The TFI system is the points(sensor pulses fire coil) and module is the condenser(smooths voltage recovery)
These require far less attention than mechanical points but they do not last forever, yours is 21 years old now.
Get a volt meter(that's the new Feeler gauge) and follow the test sheet for TFI system.
 
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Old 12-10-2014
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Ron. I hope you're not ;getting double messages from me. Still trying to learn how the forum works. Anyway, I'm an idiot. It is a distributor. I'll read the site you sent me. That will be a huge help. Can't work on it until the weekend when it's supposed to warm up. I'll let you know. Forgive my ignorance. Thanks, Bill
 
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Old 12-10-2014
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I think that's what RonD is also saying...you have a distributor, but it no longer has a set of points that you have to gap, nor a condensor per say. This distributor still distributes the spark from the coil to each spark plug wire/spark plug.

Here's a link to read up on for testing the coil. Best to first verify the coil is good, then move forward towards the distributor, it's cap, rotor, then plug wires, and spark plugs, if this is ignition related for your rough idle:

Part 1 -How to Test the Ignition Coil (Ford 2.9L, 3.0L, 3.8L)
 
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Old 12-12-2014
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Thanks for the link. Ron sent me several as well. Looks like I'm going to have a busy weekend if the weather lets up. Who ever started the rumor that 'ignorance is bliss'? Turns out it's not blissful at all when it catches up with you...Thanks for the help!
 
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Old 12-12-2014
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That is one of the problems with the new "fangled" electronics on vehicles.

They don't need adjustments and they last a long long time.
So when there is a problem we learn how much we don't know about this stuff.
And need a crash course in what things do.

In the "good ol' days" we had to mess with carbs at least a few times a year if not more, and points, lmao..........darn things wore out fast.
Reset spark timing.......jeeze.

This wasn't "easier" it was just we had to learn it over time in bits and pieces, so you just accepted that was the way it was.

Give me EFI and distributorless ignition everytime, way more reliable, but it isn't bulletproof, so we just have to accept the fact we are ignorant about something until we learn it, just like we were with carbs and points at one point
 
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Old 12-15-2014
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Originally Posted by RonD
...


Give me EFI and distributorless ignition everytime, way more reliable, but it isn't bulletproof, so we just have to accept the fact we are ignorant about something until we learn it, just like we were with carbs and points at one point
I'll take the fuel injection and electronic spark systems any day over points, condensors, and carbs anyday! Soooooo much more efficent. And yes, easier to work on IMO.
 
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Old 12-17-2014
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Hello, my name is jordan and i'm new to this forum. I'm having trouble with my 2001 ranger 3.0 5speed 2x4 with 167k miles. It started idling rough a couple weeks ago so i cleaned the MAF, IAC, Throttle body, and replaced the TPS. Initually it seemed to run better and the check engine light went off (now back on), but it's still not running right. It has less of a rough idle now, but the RPM's are sluggish to come down while shifting and the RPM's rev up to about 1300 when coming to a stop then back down to around 1000. I went and picked up a fuel filter and PCV valve, which i'm gonna replace next, and had them run a dianostic. It said my computer was still cycling, but it had a TPS error code and a misfire in cylinder 6. gonna change the spark plugs next and possibly just replace the IAC and/or EGR. Any suggestions on this?
 
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