Ndb

I've have a 91 trams am gta with 5.7 tpi.
It runs great when first started but after it warms up
It wants to loose rpm's when hitting the accelerator.
I have put a new oil send unit, temperature and fan control sensor.
Also the iac and tps( it is set at .54 volts)are new! Any ideas? It is not running hot but acts like one would with power loss and engine idling down, very confused!!!!
Oh, I have replaced fuel pressure reg and the connector to all sensors. The engine isn't on , and no errors.

KMdoza7

iTrader: (1)

Are you getting a SES light? you might have to adjust the idle speed and your gonna need a voltometer to make sure your TPS is adjusted right

Ndb

Ses light ? No engine light ( no errors) if that what your asking, and the tps is set at .54volts

KMdoza7

iTrader: (1)

check your vacuum lines and also your sparkplug wires see if the have any cracks in them they could be cross firing. just a thought

Ndb

Vacuum lines are hooked up, ( according to diagram ) but in a book I did see a little black thing ( diffuser) that looks like it hooks to throttle body ( idk where other ends hook.)Can't find anything about it. But that is only thing not on engine, the diagram on engine does not show that black thing. I have out new plugs and wires on it

KMdoza7

iTrader: (1)

im not really sure what your trying to say you might have a wire that came unhooked. but check your connections to your MAF, TPS, and IAC sensors, those are all by the throttle body.

KMdoza7

iTrader: (1)

wait, yours is a 91 so it doesnt have a MAF sensor it has a MAP sensor, see if its pluged in.

Ndb

Replaced map sensor as well , the vacuum line are hooked up accord to diagram on car but in a repair manual it show a little black thing they are calling a vacuum damper hooked to throttle body( see attached pic ) idk what it all hooks to and don't know if it is causing prob

TTOP350

iTrader: (8)

OHM check the injs,
have the ign system parts tested, coil, ign mod and pickup coil.
fuel PSI when problem occurs

Ndb

New injectors , coil was replaced last year and put new ing pick up in it

jas2730

iTrader: (7)

Just because something is new doesn't mean it's good. I can't tell you how many times i've taken something new out of the package just to find out it was a dud.

KMdoza7

iTrader: (1)

if you say that there's no vacuum leaks then that piece shouldn't be the problem. That piece is close to the canister, most people replace those with a T fitting. But I would just double check all the little things first, IAC, TPS, Sparkplug wires for cracks, MAP sensor, when you start the car can you hear any whistling sounds coming from the engine? also make sure your base timing is at 6* BTDC

Ndb

Ok here is latest , I have replaced map sensor again and the tps . What I have discovered is that the tps keeps losing it's base setting of .54
I replaced the connector as well. After it is driven couple days the tps has to be readjusted then after that I have to replace it! The one that suppose go to my car from autozone, advance and orielly's is made wrong with no adjustment holes, so been using one two years previous , I don't think that would be causing my issue but???