Bad mpgs after trans swap

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Feb 17, 2014 | 02:17 PM

#16

CCKen

CF Veteran

Joined: Aug 2010

Posts: 8,357

Likes: 103

From: Canton, MI

Year: 1999

Model: Cherokee

Engine: 4.0

NTK Sensors:

Upstream, 23151
Downstream, 23099

Rockauto has the best prices I think.

Feb 17, 2014 | 02:22 PM

#17

XJwonders

Thread Starter

CF Veteran

Joined: Jan 2013

Posts: 19,219

Likes: 45

From: west chester, pa

Year: 1999

Engine: 4.0

Quote:

Originally Posted by CCKen

NTK Sensors: Upstream, 23151 Downstream, 23099 Rockauto has the best prices I think.

Thanks!

Other than o2 sensors, what possibly could be the culprits? So I can check them out at the same time

Feb 17, 2014 | 04:00 PM

#18

CCKen

CF Veteran

Joined: Aug 2010

Posts: 8,357

Likes: 103

From: Canton, MI

Year: 1999

Model: Cherokee

Engine: 4.0

Quote:

Originally Posted by XJwonders

Thanks!

Other than o2 sensors, what possibly could be the culprits? So I can check them out at the same time

Let's see...let me get out my crystal ball..

Are you sure you exhaust manifold is not cracked at all?

Cracked exhaust upstream of an O2S will make the O2S think the mixture is lean, and then the PCM is tricked into thinkng it should enrichen the mixture.

Feb 17, 2014 | 04:33 PM

#19

NFJ79

Member

Joined: Jan 2013

Posts: 231

Likes: 0

From: Albuquerque, NM

Year: 1998

Model: Cherokee

Engine: 4.0 I6

How many times have you calc your mpgs? Did you try resetting your PCM?

Feb 17, 2014 | 04:52 PM

#20

XJwonders

Thread Starter

CF Veteran

Joined: Jan 2013

Posts: 19,219

Likes: 45

From: west chester, pa

Year: 1999

Engine: 4.0

Quote:

Originally Posted by NFJ79

How many times have you calc your mpgs? Did you try resetting your PCM?

It has been one year and 1 month since I start calculating my mpgs and I'm doing it every time I fill up. I have pages filled up with all data.

Should I reset the PCM? Is it taking leads off battery and touching them together for 30 seconds?

As for manifold. When I took the downpipe off, I tried to visually inspect the collector tube on the manifold and it seems that there's no crack on it.

Apr 2, 2014 | 09:30 PM

#21

XJwonders

Thread Starter

CF Veteran

Joined: Jan 2013

Posts: 19,219

Likes: 45

From: west chester, pa

Year: 1999

Engine: 4.0

I just had time to do work on the jeep... I just cleaned all engine sensors' ground locations, using this site..

http://www.naxja.org/forum/showpost.php?p=245993828

I'm gonna drive it around for a while and see if it improves.