1993 Buick Lesabre Self Acceleration

No I havent. I understand you connect a pressure tester on a valve that's along the fuel lines that run on top of the engine. Thing is I dont have the money right now to buy a tester or take it to get tested. But just for the record, what could the possible cause if the fuel pressure does turn out to be low? That way I can start looking at prices for when I do get it tested and I end up having to replace something. Thanks.

Well I live in south Texas and yes we have both stores available although I usually go to Autozone. I called them but they said they dont lend the tester out, they just sell it. I will try Advanced Auto tomorrow. As for your 3 theories, I think that a bad injector is more likely. I say this because I replaced the fuel filter about a year ago and from what I've heard, it usually takes longer for it to get clogged to the point of needing replacement. As for the bad pump, Im inclined to think that's not the problem because I've read that when is bad, you experience a certain kind of jerking or loss of power when going at high speed. And honestly my car actually runs pretty smooth and doesn't lose power when Im going over 50 and I step on it hard until I reach 90 or so. And even when I keep at that speed for a little while, there's absolutely no jerking of any kind. So I guess my main question is, does the pressure tester pin point the exact cause of the problem or not?

Ok well I will get it tested as soon as I can and I'll let you know what I find. Thanks again.

Hello again. I am very close to buying the fuel pressure tester that I need for the previous problem I mentioned. But in the meantime I have another question. My car was recently leaking transmission fluid, so I took it to this place where they fix transmissions. They said that two of the seals/gaskets were cracked so they had to be replaced. One is supposed to go on the side of the transmission and the other one on the rear side of it. Anyway right after I picked up my car I noticed that once I hit 50 mph or so, the entire car started shaking pretty badly, you could see it especially on the gas and brake pedals and the steering wheel. It DID NOT have that before. I asked them beforehand to check if the torque converter bolts were loose because it did used to rattle a little but only when I had it on Drive and was holding the brakes at the same time. But before their service, I could've accelerated from 0 to 80 and not feel any continuous shaking. Now even the faint rattle it had while at idle feels worse. I plan to call them tomorrow but I just wanted to know you're opinion. Thanks again.

Well it turned out to be the tires that just needed balancing. Ok I just tested the fuel pressure with the new tester I bought, and as far as I can tell, pressure does seem low.
I found this piece of information on google, although I can't say if it's 100% correct. It said the pressure should be 48-55 psi (with ignition ON) and that there should be a 3-10 psi loss at idle. So I turned the key to ON, and it reads 43 psi, and it stays there. Then I turned the engine on, and it dropped to 36 psi, and stayed there. Then I turned the engine off, and in 30 seconds or so, it goes back to 43 psi, and stays there again. I repeated this process like 4 times, so these numbers are final. So while pressure is not extremely low, I've read that in fuel injected vehicles like mine, even slightly low pressure will affect it negatively.
So in your previous comment you said low pressure reading is caused by either a bad pump or a clogged filter. I will try the cheaper option first, and if the problem persists then it's got to be the pump right? I'll let you know next week when I change the filter. Thanks.

Well I changed the fuel filter and I rechecked the fuel pressure with. The tester I bought and nothing has changed. The fuel pressure remains the exactly the same. The old filter didn't look very dirty either so that wasn't the problem. I know you said the other option would be a bad fuel pump, but do you think there's a chance it could be the fuel pressure regulator? Both parts are $100 each, so there's no cheaper option but the pump is so much harder to change on my car than the regulator. So if there's any chance that the latter could be the problem I would be very happy to try it first. What do you think?

Well I unplugged the vacuum line connected to the fuel pressure regulator and it did have a faint smell of gasoline. So does this mean my FPR needs to be replaced?

A few updates. I checked the vaccine line to the regulator again but this time with the engine running and it didn't really smell like anything. Also I read online about a test you can do to check for either a bad regulator or a bad pump/clogged filter. It basically consisted in moving the throttle with the engine on while having the fuel pressure tester connected. The pressure was supposed to rise about 5 psi, which it did. The other test was to unplug the vacuum line to the regulator with the engine on, in which case the pressure also to rise fom 5 to 10 psi, which it also did. So if we go by this test then both the pump and the regulator should be good. A friend told me that bad spark plugs also cause a rough or fluctuating idle. Is this true? I ask because it's been a couple of years since I changed them so I wouldn't be surprised if they're bad. Thanks.

MORE UPDATES: I changed the Spark Plugs and the wires, and while I did notice that the car now turns on instantly (unlike before that it would stall for a second), the erratic idling is STILL present. Also I called Autozone and they gave me the actual fuel rail pressure specified for may car: 41-47 psi with ignition ON. So my car's pressure's been good all along. So what's next?

No codes present this time. I will try the vacuum test as soon as I can buy a tester. Might be a while though. I'll stay in touch. Thanks.

Ok hold on what's the name of this tester and where would I connect it because the guy from Autozone said they dont sell anything to check the vacuum lines. What exactly should I ask for?