Hello,
I have a 1990 30zx na automatic, within the last year 2 years I have installed new bosch fuel injectors new (very costly) new Bosch fuel pump, timing belt, water pump, radiator, denso alternator, rotors, changed all fuel lines beneath plenum, all work done by Pons z specialist in Miami, I also purchased a catback system 3inches big mistake because I dont have a TT i should have gotten a 2.5
heres the problem the MPG im getting is killing me about 9mpg! The transmission takes a ahwile in the morning to warm up but after that it runs fine with just a little hesitation to shift from 1 to second gear, it idles at 1k in park maybe a little high but? I have about $2000 i want to invest into car i was thinking transmission and maybe getting the 2.5 catback, straight pipes, but im not going to drop another dime untill i fix the MPG issue, car runs smooth but doesnt peel out, is this normal? what could I do or should I be looking for TPS? I just dont know please any input would be greatky appreciated, thanks

 

You car may be rejecting the German parts you have installed, Bosch belongs in BMW's. never have had much luck with Bosch in my Z's. You should be getting a lot better mileage, like 25 or so, my 300zx averaged about 27, almost 30 on long trips, I drive with my foot in it most of the time. Did you go with a larger injector ?, if you did and you didn't upgrade your ECU then you are probably running very rich and wasting gas. You are burning about twice as much gas as you should be, in a fuel injected car there are not to many options to consider as far as changing fuel throughput.
Adjust your idle down a bit too, like 750-800
here is a link on a quick how to
Adjust Your Idle's RPM Level on the Nissan 300zx

JK on the Bosch stuff, hehe

 

Yeah could be but I got the Bosch 62018 which are the correct injectors, ill try to bring down the rpms but don't think that'll help much with the MPG, im thinking somewhere im just running to rich, just don't know where/ ive taken it back to Pons but he says no codes are appearing, car runs smooth but i feel as if it could be faster upon take off, doesn't peel out but im thinking its because i put a 3inch catback so not the correct backpressure therefore loosing a little torque? don't know if that has anything to do with it.
i remember one time that mechanic changed the computer for a tt's he had sitting in the back ( he has a few cars in the lot that are his and does this often) he installed in in mine, I questioned him if it'll work in my car being I have an NA he said yeah, this morning i called him to remind him of that thinking maybe it needed to be adjusted but he just said that it would be hesitating and not running right and that wasn't it. He seems to think that there's nothing wrong with 9mpg or just does not have the answer to fix it. Just dont know what else?? any suggestions?