Sometimes, when my foot is off the throttle and the engine revs get low (say under 1,000), the engine cuts out. The first time this happened it happened frequently over a couple of days then the problem disappeared for a month or so. Now it has returned and is more frequent.
This occurs primarily as I come to a turning. Hence I'm using the brakes, foot off the throttle. If I can keep my foot on the throttle, I can sometimes avoid the engine cutting. But this is dodgy driving behaviour.
The fault is however, intermmittent. It has occured once or twice when I've been cruising towards an exit ramp about to leave the motorway. Most of the time, it's at very low speed, on local roads, just before turning.
If I sit in my driveway with the engine idling, the revs may fluctuate and the engine may cut out - but not always.
Engineers I've spoken to have suggested the Throttle Position Sensor (TPS) is failing or that the Exhaust Gas Recirculation (EGR) valve may be sticking/broken. But nobody seems certain. The approach seems to be, "Could be X, let's replace that and see.", piece by piece.
So far,I've spent over $800 trying to get this fixed, including needing to get the computer (ECM) replaced when an engineer tried to update it.
With the replacement of the EGR quoted at over $400, I would really like a better sense of what is wrong.
About 80 miles after replacing the computer, current dashboard displayed trouble codes are: PC1571, RS0038, PZ2042. Historic codes are myriad.
Any help or advice you guys can give me will be gratefully received.