Mechanics

AUTOMATIC HESISTATION

1999 Saturn SL1

Ok so, had this problem two weeks ago:

Low coolant light was on and has been coming on every morning and it will shut off after the car warms up. < This was my initial visit to my dealership. And THEN this starts happening: the car hesitates when first accelerating from a stop light. I can feel it lag, like a small*****. Then, while its in idle it will shutter slightly. I have taken it to my dealership and no codes pop up. They checked the coolant and said nothing was wrong with it. Since taking it to the dealership the light went off. HOWEVER, they couldn't find the problem with the hesitation and the shutter. So I filled it up with some STP fuel injector cleaner and everything was fine for TWO WEEKS. Well I could still feel the***** but not so much but the shutter was gone.

TODAY: I had to fill up again this morning and the problem has re-appeared with the slight***** and the shudder. My dad thinks it's the fuel injectors but I'm not sure. Please HELP!
Avatar
Blznhot18
October 12, 2011.



It could be dirty injectors. You may want to try switching fuel stations. Also, check to see if there are any vacuum leaks on the engine.

Well this will be my second bottle of STP fuel injector cleaner. The lag was still there though even after the first bottle of STP, it just got worse when I filled up today. I've been going there for years without any problems. I can't tell if this is an injector issue or a pump issue or a filter issue. Nothing was wrong with the engine or trans they told me.

Tiny
Blznhot18
Oct 12, 2011.
Start by checking fuel pump pressure to see if it is within spec.

How do I check the fuel pump pressure? Hopefully it's without tools.

Tiny
Blznhot18
Oct 13, 2011.
You need a fuel pressure gauge, but most parts stores will lend you one. As far as directions, go to our homepage under the DIY section for detailed instructions and a video showing it done.

Well my problem is, I've also read that fuel pumps just go bad and die they don't get better and then crap out again. That's what's happening now, the***** got better and the shudder dissapeared until I refueled.

Tiny
Blznhot18
Oct 13, 2011.
Just to add to this one I have seen those fuel pumps intermintly go from normal fuel pressure to like 20psi and run like crap.I have also seen the fuel filters cause issues because they contain your fuel pressure regulator. It sounds fuel related though havent really seen the injectors have clog issues.A bad injector here and there but those are awesome injectors when they fail usually from what I have seen you will get a dead hole. How many miles do you have on your car?Have you ever changed the fuel filter they get changed every 100,000 miles and by then they are arealmost plugged solid. You could also have water in your tank I have seen that cause all kinds of dieing and not starting bucking etc when ever it feels like it. As far as the fuel cleaner I would use chevron techron cleaner the expensive bottle thats what the mnufactures use when they have fuel issues. Also a good fuel drier not a cheap one I would run thru the tank. You might want to try changing gas stations also.

Saturntech9
Oct 13, 2011.
I've got 73,000 miles on the car and I don't believe the fuel filter has been changed from the previous owner. I'm putting my money on the fuel filter though but I will take the car to Advance and see if I can use their fuel pump pressure gauge. It just seems strange that everything was just fine or getting better and then it gets worse after refueling.

Tiny
Blznhot18
Oct 13, 2011.
Does it only happen when you fill the tank? Have you ever overfilled the tank? Saturntech, could it be getting raw into the EVAP?

By the way, you got the best tech dealing with Saturn vehicles. I go to him with some of the questions I get.

Yes that's how it seems to be, when I filled it this afternoon from almost E the lagging got worse and the shudder came back while it was idle. I hardly over fill my tank, like I may round to the next dollar but I don't like fill it into the neck or anything.

Tiny
Blznhot18
Oct 13, 2011.
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