Tuneup Help?

JamesAndTheSahara

JamesAndTheSahara

TJ Addict
Supporting Member
Joined
May 22, 2017
Messages
2,164
Location
Auburn, AL, United States
So my TJ has an hesitation issue on a cold start where it has no throttle response above 2k rpms. I'm throwing no codes but my TJ's history definitely had a sinning past. Really needs a tuneup (High idle sometimes) so I'm going to start there. Being a 98 I know I need a Rotor/Cap/Air Filter/Spark Plug Wires/Spark Plugs for a tuneup. I will probably remove the throttle body to clean it and the IAC as I have never cleaned mine (Owned the TJ for 20k miles, shame on me). Just changed the oil/filter so won't be doing that. Spark plugs will be XP985 & Napa brand wires/rotor/cap/gold air filter. Any recommendations on anything else I should do for the tuneup to get her happy again?

(Recently got a new battery/alternator so electrical is going strong, for now. Replaced my radiator & hoses last year, although that will need to be attended to in the future.)

Edit: Although I am under the impression I should clean the throttle body removed off the TJ, but would it be better to clean it on the TJ while its running (Like indicated by Stu Olsen on his website)?

Edit #2: I recently changed my Power Steering fluid, brake fluid, both differentials have new fluid, and the TCase has new fluid. I will be adding Redline MT90 onto the list above for AX15 fluid change.
 
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I'd leave the TB on and run cleaner thru it like Jerry has suggested. I need to change plugs on mine too, and replace a leaking valve cover gasket.
 
bobthetj03 said:
I'd leave the TB on and run cleaner thru it like Jerry has suggested. I need to change plugs on mine too, and replace a leaking valve cover gasket.
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My Valve Cover gasket may be leaking as well. I really need to do the big 3 gaskets on the engine as it would not surprise me if they were all leaking. Thanks! :)
 
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Check your front oxygen sensor for going into closed loop to quick, or just replace it of you have 100k+ on it. They are known to fail and go into closed loop prematurely and cause those type symptoms. Use an OEM or Denso.
 
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ohiopatriot said:
Check your front oxygen sensor for going into closed loop to quick, or just replace it of you have 100k+ on it. They are known to fail and go into closed loop prematurely and cause those type symptoms. Use an OEM or Denso.
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A couple months ago when I had the cat replaced I had the o2 sensors replaced as well. No engine codes so they are working as intended. I don’t have any extensive diagnostic exquipment to know whats going on. 3 shops have shrugged their shoulders and gave up trying to fix the issue. All three referred me to the dealership.
 
They won't throw a code for going into CL to early. Its simple to unplug just to see. If it's not the mentioned brands they're suspect.

New does not mean good.
 
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ohiopatriot said:
They won't throw a code for going into CL to early. Its simple to unplug just to see. If it's not the mentioned brands they're suspect.

New does not mean good.
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I couldn’t tell you what brand they are. I’ll figure out how to check em and pull em when I get a chance (in a week or two).

Edit: thank you so much for the advice though.
 
Yes, that will make it stay in open loop. If it runs good them remove and replace them, if it runs the same, well plug them back in and the search continues.
 
Jimbo, just unplug them from the wiring harness. There should be a pigtail connector 6" or so from the sensor. Might have a little push in tab thingy on the connector so it doesn't self unplug itself. Clear as mud, right?
 
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1512766540693618443562.jpg

Should look something like this just unplug the ones in the box from the vehicle harness.
 
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