4.0 code 171/174

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Jan 7, 2003 | 02:40 PM

ka1cu

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Joined: Jan 2002

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4.0 code 171/174

Hi guys:I have been getting the 171/174 codes,I have replaced the 3 oxygen sensors,MAF sensor,Checked for vacuum leaks on hoses and the throttle body with ether.I'm out of ideas truck has 75k on it.any suggestions would be appreciated.thanks Mike

Jan 7, 2003 | 03:44 PM

Ken00

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Joined: Dec 2001

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From: South Jersey

4.0 code 171/174

I have heard about vacuum leaks on the intake manifold/fuel rail area on 4.0s, also check for exhaust leaks and wiring problems.

Jan 9, 2003 | 07:58 PM

David S

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4.0 code 171/174

According to success stories on the forum, MAF or PVC valve(and/or hoses) if it's not o2 sensors.

Jan 10, 2003 | 04:17 AM

Torque1st

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4.0 code 171/174

Jun 26, 2005 | 07:08 PM

kennyiii_65

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Joined: Jul 2003

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From: Jax, FL

My 97 4.0 Ranger had this problem (for a few years). I finally decided to change the plugs & wires. EGR was in two pieces (rust) so I decided to take it to a shop. I has around 100k miles. After this work was done, it still ran rough. The Mech, said the upper intake manifold gasket was leaking. He was able to verify it by spraying around the suspected area. The spray sucked into the gasket area and the engine ran fine for a few seconds.

I had the gasket replaced and the truck runs like new.

Kenny III

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