sentra hesitation help

[twistedshadows]

hi i have a 96 sentra gxe (has the ga16de engine) i was having really bad timing chain raddle and the car was almost impossible to drive on the high it would surge so bad so i took it all apart the chains and the spockets looked in such good condtion i could swear they where new so i cleaned out everything i could (even blew air though the oil holes for the tenisioners) changed both lower guides and the lower and upper tensioners no more raddle and the car drove great in the city then i took the highway to go to school and after cruising for a while (doesnt matter what speed i cruise at but it only seems to happen above 45mph) the car starts surging a little and i step on the gas and it just doesnt want to speed up then it finaly down shifts and i start picking up speed againso here i am thinking the problem is proably the transmission and i was driving down the highway again and i can hear the raddle and i know now the surging and lack of power is the timing chain doing whatever the f**k it wants

so thats my problem im thinking it might be the oil pressure but it doesnt really make sense since im at speed the rpms gots to be preaty high (DAMED sentras have no TACH!!!!) but i havent had a chance to get a oil pressure gauge and throw it on there

so im VERY SORRY that this post is so long PLEASE help me this is 1 of the few times im having trouble finding out a problem with a car (im a good mechanic )

thanks you all very much for any and all helpjoe wood

oh and i forgot the car has 163,000 miles and im running 20w-50 (to up oil pressure ) and i live down in miami fl if any of that helps

[twistedshadows]

come on guys any help at all would be nice

[twistedshadows]

ok i hooked up a oil pressure gauge but at the moment i only had time to drive round the block ( before it started pouring and water was coming in through the window i had the gauge coming through) at idle the car had a oil pressure of 20 psi give or take 1 psi and while i was drivin round it had a psi of around 60 (i wish i could tell you what the rpm was but damed sentras have no tach GRRRRRR) im going to drive on the highway with the gauge when i have a chance and see if maybe im loseing pressure when the speed is held constant

and please help guys

thanksjoe

[twistedshadows]

ok i drove the car on the highway the problem still showed up but my oil pressure was right where the fsm said it should be

ok so im 60% sure now its the timing chain 20% sure its the transmission and 40% sure I HAVE NO CLUE i unpluged the egr so i know its not that it has new plugs and wires like i said before new upper and lower tensioner and new guides the timing is DEAD on the ignition timing is also dead on i get no check engine light im at a complete lose

joe