Pep Boys suggested long block
 

Ok, for the past month, the idle on my 2005 Mx5 NA (with 106k miles) got worse n worse. It finally got to the point that white smoke and gas were coming from the exhaust.

I cleaned the MAF, throttle body, changed plugs, coils and wires.

It continued.

I took it to Pep Boys 10 minutes away. At higher rpm the car pulled fine, the idle smoothed out as if nothing were wrong. Once I parked, the rough idle and smoke returned.

Pep Boys kept the car 4 days only to tell me their "Master Tech" said the engine was blown, zero compression in the 2 cylinder, and recommended a long block.

I couldn't understand the "zero compression". At speed, he car was smooth and symptom free.

My wife suggested I bring it to an older gentleman that had his own shop that came into the bank she worked at.

I dropped it off, and he called a few hours later and said compression was fine. He suspected a wire issue.

Today he called, he found 3 frayed wires, one of which was the ground for the fuel system. He said that instead of the fuel pulsating from the injectors, it was a continuous spray. This caused the engine to basically drown itself and excess gas to get into the exhaust system etc.

He fixed the wires and I was on my way. The car runs like a champ.