idle issues

[Redhawk]

question for the collective? my 88 4.0 L fuel economy is bad i started driving it regularly due to the F 350 super duty costing an arm and leg to drive. motor has roughly 150, miles on it (original motor). my issue is i noticed the cold start idle was searching for an idle. not bad but noticeable. and power was lacking on the highway. reading that the O2 sensor controls the fuel and spark and i have not ever swapped it out i changed it this weekend now the thing almost dies searching for idle. quits searching after it warms up and power is back. so how do you do diagnostic on this non OBD2 computer?       

[jdog]

With a dvom and cruiser54.Com

I would start with 1-5, checking the intake bolts and checking/ cleaning the iac. Last tune up? Probably should check plugs and wires as well

[Redhawk]

Tune up done a few weeks ago everything replaced. Recleaned the ilc. What is cruse54. Com

[fiatslug87]

You can buy a RenixEngineMonitor https://nickintimedesign.com

 

Check resistance between A & B on the O2 sensor, should be 5-7 ohms. For me aftermarket O2 sensors have not worked properly, try to find a Mopar one.

 

cruiser54 is a member on here that put together a bunch of tips/procedures to diagnose/fix problems with our Jeeps. http://cruiser54.com/

[cruiser54]

Cruiser54.com is my website dedicated to your era of Jeep.

 

Complete Tips 1 through 5 before spending any more time and money on anything else. 

[VorTekX]

On 8/8/2022 at 2:30 PM, fiatslug87 said:

You can buy a RenixEngineMonitor https://nickintimedesign.com

 

Check resistance between A & B on the O2 sensor, should be 5-7 ohms. For me aftermarket O2 sensors have not worked properly, try to find a Mopar one.

 

cruiser54 is a member on here that put together a bunch of tips/procedures to diagnose/fix problems with our Jeeps. http://cruiser54.com/

Do you know what the part number for a mopar 02 sensor is?

[cruiser54]

I don't. Have you checked the resistance as outlined above by fiatslug87?

 

Have you completed Tips 1 through 5 on my website? 

 

I wouldn't buy one more part before doing those things. 

[fiatslug87]

2 hours ago, yungupgrade said:

Do you know what the part number for a mopar 02 sensor is?

04713639

But agree with cruiser54 about checking other things first.

[cruiser54]

Yep. Could be a bad ground, poor connection, dirty relay receptacle. 

[Redhawk]

ok grounds tested cleaned everything else done. put the old o2 back in and it runs right again. must be the after market sensor? also cleared the memory may have helped.

but all in all great site and thanks cruse54 and all others for there help.  

[cruiser54]

Or the grounds?