1999 FORD RANGER 1999 FORD RANGER P0306 P0174 PROBLEMS...?

  • Tiny
  • doner8749
  • 1999 Ford Ranger

Engine Performance problem
1999 Ford Ranger 6 cyl Two Wheel Drive Automatic

My Check Engine light came on 2 weeks ago and I did a scan, p0306 and p0174. I relize 306 is misfire cylinder 6 and 174 is a lean code but im lost where to go now. I have replaced the coil, spark plugs, wires, DFPE sensor, egr valve, Replaced injector 6, Cleaned MAF and I am still getting these codes. I am absolutely stuck now and need a guide on what to do next or what possiblities would cause these codes, and are they related some how? Also I have been getting the p0306 for awhile now but the 174 started to come when I added my new Cold Air Intake, and yes I have tested for leaks and there are none PLEASE HELP ME! Thanks!

Tuesday, April 8th, 2008 AT 7:18 PM

11 Answers

  • Tiny
  • cookie1
  • Member

My 1999 Ford Ranger had the same problem, I was getting the same codes. It was driving me crazy. It wanted to skip and jump on acceleration. Then one day I remember that I replace the plugs with pre gapped plugs, so I decide to check the plugs gaps. They were set wrong from the factory they were set at .065 when the book calls for.055. Cure all my problems after resetting them to right gap.

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Wednesday, April 9th, 2008 AT 12:04 AM
  • Tiny
  • doner8749
  • Member

I do not believe it is the gap settng considering I have tried three different types of spark plugs. The Plugs I have now are LSG Brisks, which you cannot set the gap if you look at the design. Which they are gapped to.44 permenantly. Please help?

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Wednesday, April 9th, 2008 AT 6:31 AM
  • Tiny
  • Jack42
  • Member

First of all, get rid of those plugs and install the Motorcraft's that it calls for. Sounds like it may have sucked the intake gasket on the #6 cylinder.

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Thursday, April 10th, 2008 AT 11:46 AM
  • Tiny
  • flexy5
  • Member

I agree with Jack. The P0174 code is the key. It registers lean on bank 2 which is the bank that cyl 6 is on. If it was a plug issue, that would cause an incomplete burn in fuel which would register a rich code. Lean codes are almost always attributed to intake concerns. And with the misfire code, I would bet on the intake gasket.

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Thursday, April 10th, 2008 AT 3:36 PM
  • Tiny
  • doner8749
  • Member

I just picked up a new intake gasket set and will let you know if its clears it. Also I have noticed that the light is only triggered on cold starts. When the engines warm or if its later in the day it does not come on. Hope it clears : )

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Thursday, April 10th, 2008 AT 6:05 PM
  • Tiny
  • doner8749
  • Member

So I purchased a gasket set from Fel-pro, and took the truck into the shop. They Replaced The Intake Gasket and 100 kilometers later the light p0306 light comes on still. The p0171 code cleared, the mechanic said it was because of my oiled air filter wasover oiled and the MAF was dirty, cleaned it up and hasnt returned. But now im stuck, Ive Also replaced the Spark Plugs with Autolite OEM plugs, Wires, new Coil, Intake Gasket, Fuel Filter and the problem still persists. Any other ideas?

Thanks Alot!

David Doner

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Monday, April 21st, 2008 AT 3:18 PM
  • Tiny
  • flexy5
  • Member

Do you know if they replaced the uppers, lowers or both on the intake? If it's not an intake problem, then it only leaves the injector and valve issues. Also, is this a 3.0 or 4.0? That might be helpful knowledge for further diag.

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Monday, April 21st, 2008 AT 9:18 PM
  • Tiny
  • doner8749
  • Member

Yes they replaced both the upper and lower intake, also the idle air control gasket, The injector has already been replaced with a new one, code came up again, swapped it with one of the other working ones and sure enough the code came up again. It Is a 3.0 Litre

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Monday, April 21st, 2008 AT 11:17 PM
  • Tiny
  • flexy5
  • Member

If we have considered all the obvious, then we are left with the obscure. You may want to consider the possibility of a sticking valve. Does the vehicle run rough at all? The other possibility os poor compression when cold.

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Wednesday, April 23rd, 2008 AT 10:27 PM
  • Tiny
  • doner8749
  • Member

I took my truck into the shop and they think that it might have been a leaking injector since spark plug 6 was brown and the rest were not, but im not so sure since it is a brand new injector. They ran a high concentrate injector cleaner and cleared the code with there scantool. They tested all of the gaskets and they were fine, does that seem right?

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Saturday, May 3rd, 2008 AT 2:37 PM

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