Meriva A 1.4 losing power, intermittent faults

[Meriva2222]

Hi,

My '59 plate Meriva A 1.4 has developed a problem in the last week or two. It has started to lose power when trying to accelerate in 4th or 5th, and stuttering/limping when holding a constant speed eg 40mph @ 2000rpm in 5th gear. It will start slowing down as if I've taken my foot off the accelerator even though I haven't, and the car judders a bit before picking up again. Same when trying to accelerate, put my foot flat to the floor at 40mph and nothing happened, then after about 10 seconds the engine revved and it finally picked up speed. All this is intermittent and no warning lights have come on. I've checked for fault codes with a code reader and found nothing. All fluid levels are ok as well and it had an oil change about 2000 miles/3 months ago. Hoping it isn't anything terminal and continuing to drive won't damage it :(

Any help would be greatly appreciated.

[Meriva2222]

Also forgot to add that it revs absolutely fine in neutral and engine sounds alright as well