hi this is rather a complicated and drawn out post so bear with me
we have a 1996 ls 400 some weeks ago we lost a secondary 02 sensor had this replaced only to find we had the dreaded split egr pipe (forgot to say car has been converted to lpg ) we did the delete rather than replace the pipe still have valve connected but blanked off sinc doing the delete car runs OK but will not accelerate properly and uses excessive fuel (like 1 mile to £1 of fuel) not good also wont switch over to gas as quickly as before its an obd1 and have managed to get some codes out which are as follows 21,27,28,29,31.71 replaced air filter and tried to clear the codes but they are still there ordered another maf thinking that might be the problem but am now at my wits end trying to sort this out car ran well before the lambda senser blew out although it had a blow on the exhaust which was welded up heres hoping that someone on here can help please just 1 other thing car used to start 1st time every time before this trouble now it takes 2 or 3 goes to get her going