For a fuel injected, in-line three cylinder 1.0 litre gasoline engine (specifically X10XE I3 found in Opel Corsa B), what is the most statistically likely cause of the following problem, and what checks (if any) should be performed to investigate the problem further, to narrow the possibilities?
- Poor performance at low RPM.
- Normal performance at higher RPM.
By "poor performance" I mean there is a "hole" in the power curve of the engine. At wide open throttle starting from low RPM, the engine will at first start to make power, then hesitate and deliver no performance at all. RPM will still build up, until it reaches higher RPM where the performance is normal.
This is a weak engine by design but the normal curve of it certainly doesn't feel like this.
There are no bad engine sounds during idle nor acceleration. Idle is fine. There is no visible smoke from the engine nor exhaust. The ECU has not lit any ECU warning lights.
The age of the engine is 17 years. It should be noted the engine has been driven at unusually low RPM for these 17 years, if this matters. It probably never saw high RPM and especially not higher RPM and WOT at the same time. Driven ~45 000 miles. Service schedule followed.
No attempts at repair has been made, OBD has not been checked.