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Timing chain and sluggish acceleration

My car runs mostly on CNG. Even when i adjust the timing to run on petrol, it’s a bit sluggish. There’s an occasional ‘tackety-tack-tak’ sound coming from near the valve cover from the timing chain side. A bit like tapping thick metal object lightly. Could a loose chain cause poor acceleration? The sound isn’t always there. Comes on around 1100rpm, can’t hear above 2000. More noticeable when engine oil drops a little low.

No,a loose timing chain will not cause sluggish performance. I will with hold any additional “check this” type of ideas because you did not provide any details about what type of vehicle we are working on.

CarTalk is a “full service” facility. If you provide good info we will go to extremes to come up with a answer or a direction for you to take, the more pertinant details the better.

Ah, really sorry for that oversight. Car’s a 1991 Nissan Sentra 1.5 (carbureted) with a 5MT with about 95000 km. Previous owner may have been a little dodgy in maintenance. My brother has same car. His car goes to 55 kmph in first gear without redlining. Mine does barely 40+. That too rather slowly.
2 months back had clutch, pressure plate, release bearing, rear seal replaced but not much change in acceleration. Neither car has any aftermarket engine mods. Both cars are early JDM versions = no cat.
Also wheels roll freely. Alignment spot on. Tires are factory spec. Plugs and cable good and clean. Engine rpm goes equally bad when each plug cable is pulled (haven’t done compression test). Get a little white smoke on cold startup but then clear. Dunno what else I’ve left out.
Would appreciate help on why it won’t pull and whats’ with the ‘tackety’ noise.

It seems like you are impliying that the clutch is slipping (because you speak of redline) is it. Has some service manual indicated ithas a timing chain? have you taken a look at an exploded view of the chain setup? what type tensioer does it use,one that relies on oil pressure?

What i meant is that i accelerate just close to redline on the tach. I don’t like pushing engines too much. But top speed in first gear of both identical cars are different. Mine feels like it has a hard time reaching speed. Could improper spark timing also cause sluggish acceleration?
Yes, car has timing chain. Not sure if tensioner relies on oil pressure but keeping oil topped up keeps it quiet. A little low and i get the intermittent tapping noise.