Engine looses revs, backfires then next day works perfectly!

[bobmac]

Hi,
Have a 91 Petrol, runs fine except 2 days ago in afternoon driving home the vehicle started to shudder then I noticed the revs were dropping when at low speeds, when I got the vehicle back up to 80kph the revs held but dropped slightly every 2 seconds then came back again. Next morning, engine started fine, drove to mechanics and he couldnt find anything wrong after brief look at distributor. Drove it home in the afternoon, 15 minutes into the trip same problems started again, this time with backfiring through the exhaust - this morning, it started fine and just drove into town there and back (20 minutes each way) with no problems! Each time problems started, was in the afternoon and (coincidentally or not) driving up hilly roads. Any ideas?

[taslucas]

Possibly starving for fuel? When was the last time the filters were changed?

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[threedogs]

Maybe even perished vacuum hoses. just do one repair at a time.
that way youll know what the problem was

[4bye4]

driving up hilly roads

. Might be a clue. Only doing it under load. The previous idea from Tas sounds good, also maybe a vac advance line leaking or split off its attachment point.

[bobmac]

Just started the car after 2 hours, problem instantly came back, revs wont hold especially at low revs - see the vid when foot is steady on the accelerator:

https://www.facebook.com/bob.mcgilvr...2479639520904/https://www.facebook.com/bob.mcgilvr...2479639520904/