Hi,

I'm about to lose it here. I'll start at the beginning. I replaced the fuel pump by using the chevy pump inside the fuel pump housing. Worked except it was very hard starting. So I replaced the hose from the pump to the pump housing with a longer looped hose thinking that it was losing pressure and therefore hard starting. I looped it so that it would not restrict the passage of fuel when the pump compresses. THe hose itself was a standard black flexible fuel line hose that you would buy from any pep boys or auto zone. Another thing I did during this was replace the fuel injectors with new 19lb bosch injectors. New brakes and shocks too, but that should have nothing to do with this.

I drove it yesterday and noticed the idle dropped low (400-500) after I drove it for a minute, but then it came up to 700 or so and was fine for the rest of the drive (figured the ecu was getting used to the new injectors). It was running smoother and stronger than ever before. So today I fill up after maybe 5 minutes of driving, drive another 30 minutes no problem (although I did notice surging). After I get off the highway and drive for a bit I feel the the car slowing as if my foot is not on the gas. Then it speeds up for a second and dies for a few seconds (over and over), then give gas, then not. Stopped at a light, it would die, but start right back up again and do the same thing. I make it to work and it dies in the parking spot. An hour later or so I go to see what's going on, car starts right up, but idles at 1500. Put it into drive or reverse, it drops to 700.... put it back into park or neutral, shoots back up to 1500. So I drive it around for about five minutes and it drives fine and doesn't stall..... but put it into park, back to 1500!!!! What's going on?? Any ideas?!? Vacuum leak? Gas ate the hose on the pump? Hose on fuel pump is restricting gas flow when the fuel pump is compressing? (I checked before I installed it and it looked like it wasn't at all. Could I have gotten something in the fuel line and clogged the fuel filter? Anyone have this happen before? Thanks!

T

 

Year and model will help!!

 

damn it, sorry..... I usually use another forum but it's down.... 97 Discovery.

 

So, welcome to the site.
You might consider adding information about your truck so we have a better idea of who you are and what you truck is like.
So, have you cleaned your t/body, your IAC, checked for vacuum leaks, replaced your fuel filter. How about your fuel pressure, have you been checking it at the rail when it acts up?

 

think Mike got the good questions already...

 

THanks.... ok, this morning is the first time it happened. I just cleaned the IAC and the throttle body and checked for vacuum leaks. Afterwards, it idled at normal for a few minutes and then went back up to 1500. As far as vacuum leaks, where are all the spots that I should be checking, maybe I'm missing a few. Pressure at the rail has been between 30 and 40psi a few days ago, but I don't have a guage with me so I haven't been able to check anything today. Fuel filter I haven't done yet, it was replaced a year ago, but I'm thinking something might've gotten in the line when I changed the fuel pump? Would clogged fuel filter cause high idle? Should it take a bit of time for the ecu to adjust to the new injectors and pump?

 

Check your intake to left rocker cover line. It may look fine but be collapsing. Also there is another line on the right rocker cover to intake. Take this line off, and you should find what looks like a little plastic crankshaft. It is an oil separator, make sure it is clean and that the hose is in good condition.

A plugged filter would make it cut out under load and at high RPM.

 

ok.... I have a new filter at home so I'll see if I can get those connections open and swap the filter out. I'll check those lines as well.... aren't those breather hoses? I have another IAC at home so I'll swap that out too and see what happens and let you guys know, if anyone has any other ideas, lay them on me! Thanks.

 

ok.... I checked those hoses and cleaned everything as best as I can and now the idle is way up to 2500 afterwards..... the little plastic oil seperator, what would be the best way to clean that?

 

pull it out and douse it with carb cleaner.

Sounds like your ECU is not reading your IAC correctly, letting too much air in. Plug your breather ports (mostly the passenger side) and see what happens.