Novak Conversions Jeep Wrangler TJ radiator

2003 Jeep 4.0 sputtering

Roach1620

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Jun 24, 2025
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La Verne CA
My 2004 jeep tj 4.0 sputters only when coming to a stop. Seems to be worse on cold days. Cleaned IAC and throttle body. Fuel pressure is around 48. No check engine light and drives fine only has issues when coming to a stop . Jeep does seem to idle rough when in drive.
 
Shouldn't be. 2004 doesn't have the OPDA, just a regular camshaft position sensor.

Timing advance is pretty weird in the TJ but should be reasonably stable at idle. I can't pull the stock timing tables for a couple days but assure you the range swings from single digits at low rpm WOT to 45 degrees and is anything but linear.
 
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This is my modified timing table (timing increased a few degrees on 79.1 and 92.3 kpa rows). Idle is normally 672 rpm on the 04 so you should see stable around 24. I've bumped mine up because the MORE motor mounts are quite bombproof and smooth out at 800.

1754106782891.png
 
This is my modified timing table (timing increased a few degrees on 79.1 and 92.3 kpa rows). Idle is normally 672 rpm on the 04 so you should see stable around 24. I've bumped mine up because the MORE motor mounts are quite bombproof and smooth out at 800.

View attachment 634253

Even when idling it jumps around. Rough idle and miss fires when coming to a stop and it's cool outside
 
Even when idling it jumps around. Rough idle and miss fires when coming to a stop and it's cool outside

Can you see the LTFT and STFT fuel trims on bank 1 and 2?

Misfire codes and bad idle make me think maybe bad coil rail or plugs. Maybe bad engine ground (passenger side of firewall) or dead battery. Did you capture a code?
 
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Novak Conversions Jeep Wrangler TJ radiator