Shudder Occurs after TCC Has Applied:

In this case, most of the time there is nothing wrong with the transaxle! As mentioned above, once the TCC has been applied, it is very unlikely that will slip. Engine problems may go unnoticed under light throttle and load, but become noticeable after TCC apply when going up a hill or accelerating, due to the mechanical coupling between engine and transaxle.

Inspect the following components to avoid misdiagnosis of TCC shudder and possibly disassembling a transaxle and/or replacing a torque converter unnecessarily:

• Spark plugs - Inspect for cracks, high resistance or broken insulator.
• Plug wires - Lock in each end, if there is red dust (ozone) or black substance (carbon) present, then the wires are bad. Also look for a white discoloration of the wire indicating arcing during hard acceleration.
• Distributor cap and rotor - look for broken or un-crimped parts.
• Coil - look for black on bottom indication arcing while engine is misfiring.
• Fuel injector - filter may be plugged.
• Vacuum leak - engine won't get correct amount of fuel. May run rich or lean depending on where the leak is.
• EGR valve - valve may let it too much unburnable exhaust gas and cause engine to run lean.
• MAP sensor - like vacuum leak, engine won't get correct amount of fuel for proper engine operation.
• Carbon on intake valves - restricts proper flow or air/ fuel mixture into cylinders.
• Flat cam - valves don't open enough to let proper fuel/ air mixture into cylinders.
• Oxygen sensor - may command engine too rich or too lean for too long.
• Fuel pressure - may be too low.
• Engine mounts - vibration of mounts can be multiplied by TCC engagement.
• Axle joints - checks for vibration.
• TPS - TCC apply and release depends on the TPS in many engines. If TPS is out of specification, TCC may remain applied during initial engine starting.
• Cylinder balance - bad piston rings or poorly sealing valves can cause low power in a cylinder.
• Fuel contamination - causes poor engine performance.