Okay boys and girls, ive got a 99 xj, 4.0.
Im getting the occasional slow return to idle problem. occasionally it will just hang up about 1200 rpm for a few seconds after i let off the pedal, and shes not very consistent about it either. sometimes it just hangs there for a moment other times it seems to go up a hundred rpm before returning to normal.
otherwise she idles fine, with a slight amount of needle bob. ( i cant tell if its normal or bouncing between open and closed loop)
here's where im at:
Fuel pressure is good.
TB is so clean you could eat off it.
New IAC
New TPS (have two that test and work the same)
New Coolant temp sensor
New Up & newish downstream o2
New cap rotor and spark plugs
butterfly plate isint sticky
No vaccum leaks, i even went as far as to cap all the lines off and try taking it for a drive.
im relatively sure its not the throttle cables, it will rpm hang when i move the Throttle by hand and can see its not hanging up on the cables.
Brand new Cat last week.
its not leaking at the TB-to manifold surface. gasket is good.
after posting elsewhere i tried seafoaming. its cleaner (i guess) but still the same problem.
ECU reset.
took all the injectors out, cleaned and tested.
no Codes
TV cable set
oil and air filters up to date.
fuel filter is in the tank , and i really really dont want to drop the tank unless i have to.
tailpipe is a little black at the end, looks like its running rich, question is why perhaps?
i feel like im chasing a ghost. i just spent the last couple hours checking the resistance for the grounds for the upstream O2, wondering if maybe it was poorly grounded. less then an ohm, and 14V supply to the heater.
help?
Im getting the occasional slow return to idle problem. occasionally it will just hang up about 1200 rpm for a few seconds after i let off the pedal, and shes not very consistent about it either. sometimes it just hangs there for a moment other times it seems to go up a hundred rpm before returning to normal.
otherwise she idles fine, with a slight amount of needle bob. ( i cant tell if its normal or bouncing between open and closed loop)
here's where im at:
Fuel pressure is good.
TB is so clean you could eat off it.
New IAC
New TPS (have two that test and work the same)
New Coolant temp sensor
New Up & newish downstream o2
New cap rotor and spark plugs
butterfly plate isint sticky
No vaccum leaks, i even went as far as to cap all the lines off and try taking it for a drive.
im relatively sure its not the throttle cables, it will rpm hang when i move the Throttle by hand and can see its not hanging up on the cables.
Brand new Cat last week.
its not leaking at the TB-to manifold surface. gasket is good.
after posting elsewhere i tried seafoaming. its cleaner (i guess) but still the same problem.
ECU reset.
took all the injectors out, cleaned and tested.
no Codes
TV cable set
oil and air filters up to date.
fuel filter is in the tank , and i really really dont want to drop the tank unless i have to.
tailpipe is a little black at the end, looks like its running rich, question is why perhaps?
i feel like im chasing a ghost. i just spent the last couple hours checking the resistance for the grounds for the upstream O2, wondering if maybe it was poorly grounded. less then an ohm, and 14V supply to the heater.
help?