i recently filled my car with cng from a non-usual PSO cng pump and performance became bad. the problem was on first gear and second gear. pick was low and i if speed goes below 20 on 2nd gear, it wouldn't pick at all.. had to switch to 1st gear.
i went to workshop and they said tuning is bad. they cleaned spark plugs, and did some adjustment while accelerating - there was some nut they loosened or something)
after tuning, i was getting very nice pick and no issues on second gear too but then CNG finished and i switched to petrol.. and there was the surprise. The car has crazy idle rpm on petrol even after starting.. and slight touch of accelerator and it accelerates like crazy. and i also noticed the car became hotter than usual and a bit of smoke too once.
anyways.. do you think it was really a tuning problem in first place? i got it done from i-9 chevy workshop but i think they are not good in fixing tuning issues.
know any experts please?
edit: car is chevrolet joy