jperz89lx

ok guys i'v been having this problem for a loooong time and it has gotten worse over past few months. i'll be at idle at a stop light or just pulled into a parking spot, or in line at wendys or what ever. the rpms will drop, then jump back up, then drop, then back up ect. it will do it 3 or 4 time then the car dies, turns right back on after it dies and it will be ok for a min. then it might start doing it again, or it might be fine the rest of the ride, its random as hell. sometimes i can go for 45 min drives and it doesnt do it, and sometimes i'll drive5min to work and it will die 4 times...so heres what i have changed so far...fuel pump, fuel filter, fuel pressure regulator, the idle air control valve (that thing on the side of the TB), egr valve, and pcv valve. iv sprayed carb and choke cleaner around the upper and lower intake gasket..nothing..i just dont know anymore, im out of ideas...heres the video of the tach in my driveway just to show ya what it does...http://s199.photobucket.com/albums/a...t=5d7cb58c.flv

FuzzyDiceRule

slight, vibration induced vacuum leak?

92hatchLX

When's the last time that you cleaned your MAF sensor wires?

bmennen07

ur check engine light isnt on is it? when mine did that it was the fuel pressure regulator but u said u replaced it so ill ask my uncle to watch the video, he's pretty smart.

tmajikman

Get a can of carb cleaner and start spraying your vacuum line and see if your idle changes. Clean the IAC and maf sensor as well. This is where I would start, it is the cheapest way. Have you pulled your koeo and koer codes? Ijust found a vacuum leak the other day, the idle was going up and down likw crazy as well.

86 5.0L

this is probably one of the worst problems with the 5.0 theres been around 5 threads yesterday and mine is also doing that [:@]

jperz89lx

thanks guys...i pulled codes and it gave me a 14, 18, and a 91...

14 - is ignition profile pickup erratic
18 - is spout circiut open
91 - is oxygen sensor problem

what do you think about replacing the O2 sensors?... might help this problem or not?...whatcha think?...

tmajikman

I would replace them both if I were you. Make sure and reset the ecu and then see if you codes show back up after you replace the o2s. It will help gas mileage as well.

Joel5.0

Swap the O2s from sides and check if a code 41 shows up instead.....if it does, that sensor is kaput....codes 14 and 18 are serious though, they will also cause that problem......clear codes and recheck if they show up....if they do......need to correct them.