Hi All,
Can anyone suggest a reason why my car would be running rough when cruising at a constant speed - but be perfect when under acceleration or at idle ?
I've already changed the air filter, replaced spark plugs & leads and used 2 tanks of fuel with injector cleaner additives (nulon & flashlube)
Car is multi-point injected & has electronic ignition (1998 1.5L Proton Satria GL - 80,000 kilometeres on the clock - yes quite low !)
I would have thought that if it was the injectors or the fuel filter that performance during acceleration would be awful - but its not - its great.
The "chugging" symptom occurs when cruising at a constant speed at revs of anywhere between 2,000 - 4,000 rpm.
Its hardly noticeable when crusing on a downhill road/slope (ie. engine doing almost no work) but when on a flat road or a road with incline, the fault is fairly repeatable / consistent when travelling at constant speed. (45 kph in second gear, 65 kph in 3rd gear, 85 kph in 4th gear etc.)
Any ideas anyone ???
Thanx. Cheers Steve. M.