hello, i have a 1990 Delta 88 royale brougham and for the past 7 1/2 years was sittin gin the yard with grass growing around and under her. so far (in the course of about a year and $2000 roughly) Ive replaced all of the fuel lines, all brake lines, calipers, drums, drum springs, fuel filter, fuel sending unit, oil and oil filter, fuel pump, fuel strainer, rack and pinion-to-steering pump-to-radiator cooling lines, transmission lines, o2 censor, cut out the cadilatic converter and replaced with a straight pipe, fixed hole in the gas tank, and she is road capable!.... but.. when i start going down the road, anytime after i get almost to 30mph with the pedal down just as thought im regularly accelerating, it wont do anything until it gets almost to the floor when she kicks down and accelerates extremely fast, as normal with pedal all the way down, then wont slowly accelerate or keep speed unless gas is jammed. and when she stops, she stalls out. then will fire up normally and do the same thing over again as before.
also, when shes sitting in park ideling for about 5 minutes she will just slow down in RPM's, shake the car, and stop. The engine is a series one 3800 3.8L and i really need some help on this, any advise??

P.S. im trying to avoid taking the gas tank off for the 9th time to replace another costly fuel pump and i ant to eliminate

P.S. im trying to avoid taking the gas tank off for the 9th time to replace another costly fuel pump and i would like to eliminate all other causes before that*

Let's start with the simple things, have you checked the fuel pressure?

TOC Admin
Brando

i have not yet, how would i go about doing that and would it cost anything?
another thing i may want to add is i only have 7 days until i leave for basic training to south Carolina so i just want to drive my olds before i leave for all summer

O'Reilly, Autozone, or Advance Auto should have a fuel pressure test gauge available for rent. You just pay for the tool, then when you bring it back you get a full refund. On top of the intake manifold, there is a fuel rail that the injectors are connected to. There is what's called a "schrader valve" on the fuel rail, it should have a plastic cap that twists off. This is where the fuel gauge hooks up to.

When the gauge is connected, you turn the ignition to the ON position, but engine OFF (don't crank it). The fuel pump will run and pressurize the system. The gauge should read and hold between 40 - 47 psi. With the engine ON, it should read/hold between 31 - 42 psi. You might also want to rent a hand vacuum pump, my tool of choice is the MityVac. If those pressures are out of spec, you next pull the vacuum hose off of the fuel pressure regulator, with the engine idling, apply 12-14 inches of vacuum to the pressure regulator, it should read 31 - 42 psi. If not, then the pressure regulator is bad (round thing located on the fuel rail).
If that checks out, then it's safe to say all is functioning well, and it's a control issue. My guess would be the Throttle Position Sensor. Best way to test this is with a real scan tool that will show sensor read out...but I don't think you can rent one of those...

TOC Admin
Brando

i took a pressure tester to it and it would read at about 30 then go up to 45 then stop, so i would try that with the engine on and it would do the same thing unless i unplugged the mass air flow censor then she would run beautifully (for the most part) but i got tired of it running half well, so i took it into a mechanic and found out the computer was fried on it and was reading the information backwards so whenever i would hit the gas it would slow down and whenever i let off it would speed up (this is with the mass air flow censor plugged in) so when i replaced the EMU she ran perfectly! so i put some new rims on her, new radio and speakers, replaced fully the power steering lines and now not only does my baby run perfectly but leaks no fluids at all anymore! im very happy being able to drive a car that runs perfectly and has much better gas mileage and looks nice, i'll post pictures of it soon with a description of everything i did to it but thank you for the help, i appreciate it allot.