Here is a TSB that requires a PCM Change to repair:
Here it is: TSB# 18-029-03
Date: August 8, 2003
Subject: Slight Engine Misfire Above 5200 RPM
Here's a little more info for the non-believer(s)
TSB# 18-029-03
Date: August 8, 2003
SUBJECT: Slight Engine Mis-Fire Above 5200 rpm
OVERVIEW: This bulletin involves replacing the Powertrain Control Module (PCM).
MODELS: 2003 (PT) Chrysler PT Cruiser
NOTE: This bulletin applies to vehicles built prior to January 22, 2003 (MDH0122xx) equipped with a 2.4L Turbo engine and manual transmission or prior to March 18, 2003 (MDH 0318xx) for vehicles equipped with a 2.4L Turbo engine and automatic transmission.
SYMPTOM/CONDITION: Vehicle operator may describe a random or slight engine mis-fire when operating vehicle above 5200 rpm. There will be no DTC logged in the PCM. If there are DTCs present additional diagnosis should be done to determine the problem.
This condition is caused by a internal hardware issue in the PCM.[}
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Alan