Resolved Need some assistance. Holley Terminator X alongside H/C/I. Very rough/inconsistent idle

karhoot

Member
Apr 23, 2026
24
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CT
Hey all! Finished up doing a major overhaul & had some tech questions. Seeing if anyone can chime in.

Recently pulled motor & performed full refresh: bearings, gaskets, new rings etc. Installed XE274HR cam, AFR 1341 (185cc heads), w/ a Edelbrock Performer RPM intake. Car has 24lb injectors & a Terminator X standalone.

After a lot of back and forth with a tuner, finally got a base tune setup to get the car to idle. Everything seems fine until car hits around 130-140F CTS. Idle starts surging like absolute crazy & just does not run properly. Was looking to see if anyone can assist with analyzing a datalog of the most recent idle I've set as well as the tune currently. Car has 36psi fuel while idling & currently set at 18 degrees of timing.
Smoke test was performed on intake & exhaust. Found no traces of smoke anywhere, ruling out vacuum/exhaust leak. CTS was recently replaced as Holley's was approx 65F off out of the box. Swapped with a GM style & got accurate to MAT sensor readings while car sat overnight (ambient).

[Current datalog was a bit skewed, will post another shortly.]
 

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