I have a 1995 I6 2WD manual with about 190000 on it and i am having a power issue sometimes. Seams like it is when its warmed up but it not always. Basically what happens is it will run just fine with no problems until it get about 45 or so or i have been driving it around town and it not always the case. Sometimes it will run just fine for a whole week with no problems. Anyways....I will be just going down the road and all of a sudden it will feel like someone just cut the gas and it flicking the switch on and off. A very jolting experience. It will just continue doing this every 2 seconds or so. Then if i get to a hill or long incline it just has no power and i can push my foot to the floor with out any change it speed or engine rev and will start slowing down. I have figure out if i slowly give it a tiny bit of gas at a time it will get a little more speed so i can get up the hill, then as i reach the crest of the hill it will just kick in and go with full power. I have checked my fuel pressure and when i first put my gauge on it it was at 30 psi. Now it has been a day or so and it is at 50 psi at idle. When it was at 30 and i would rev the engine and the pressure would drop.to like 28 psi. I have not put a vacuum gauge on it yet cause i don't have one but planning on getting one. It does have full tune up and new fuel filter and fuel pump. Could a vacuum leak cause this or would it be a bad fuel regulator?

 

This should never happen pressure should always rise when throttle is opened, and 30psi is too low the I6 motor requires a minimum of 45psi at all times and upwards of 60psi max. You say the pump is new? What brand is it? Aftermarket fuel pumps do not have a very good record, some last a year, some a few weeks, some are DOA out of the box. IMO if you want OEM reliability you will have to pony up and buy an OEM pump.
That said test the regulator to see if it responds correctly and that it is not leaking through the diaphram into the vacuum line.

 

[QUOTE=Conanski;14559396OThat said test the regulator to see if it responds correctly and that it is not leaking through the diaphram into the vacuum line.[/QUOTE]

I have pulled the vacuum line off of the regulator and it does not change anything. I have read that it is suppose to rev when you take the vacuum off of it. I will check it again today to verify. The pump is an aftermarket pump and i know i should of bought OEM but it was the best i could do at the time.

 

When you pull the vacuum line off the FPR the pressure should increase from about 45psi to upwards of 60psi but the engine speed should not change, if you notice any change in the engine simply put your finger over the end of the vacuum line to stop that vacuum leak. Note there should be a constant vacuum on this line, if there isn't then it's broken. If you don't see any change in fuel pressure when removing vacuum from the FPR then either the filter is clogged, your pump is weak, the FPR is bad(they don't usually fail this way), or you have the fuel transfer problem(dual tank trucks only).

 

Well I just checked and my pressure was sitting at 35 when I started my truck and when it was idle. I removed the vacuum line and nothing changed in the pressure. Should I replace the FPR?

 

I think Conanski pretty much already told you what to check. Also make sure there is vacuum, maybe the line is busted.

"If you don't see any change in fuel pressure when removing vacuum from the FPR then either the filter is clogged, your pump is weak, the FPR is bad(they don't usually fail this way), or you have the fuel transfer problem(dual tank trucks only)."

 

Thank you for the quick reply's. I will make sure that the pump is putting out the correct pressure and work my way up to the FPR. As far as the fuel pump goes it is either on or off right? there is no voltage variance that would cause a different pressure to be put out right?