2000 neon 1500 rpm idle

[white98rt]

I'm officially stumped. i have a 2000 Plymouth I've been trying to fix. It is idling at 1500 rpm, and bounces around slightly(maybe 150 rpm on either side of 1500). i found the fuel pressure was way too low, replaced the pump and regulator with an almost brand new one i found in a jy. I've replaced the Idle Air Control and Throttle Position Sensor with known goods i had laying around, cleaned map sensor, checked injectors for a good mist, run through vacuum lines a few times looking for leaks and cracks, checked timing, checked and cleaned pcv, and probably more i"m forgetting about. If anyone has any ideas as to what the problem could be, i would appreciate any advice. Oh, and it smells like it's running rich, but that might because it's relearning closed loop fuel tables from the recent jump in pressure.

Forgot to add, it only does this in park or nuetral. put it in gear and it runs okay.

[white98rt]

codes p1684 and p1495. 1684 just means pcm memory has been cleared withing last 50 key cyccles, 1495 is leak detection pump solenoid circuit. my r/t didn't run like crap when it didn't have a ldp installed on it, or any better when i put one on, so i kind of skipped worrying about that until i figure out where it is on that car.

[UptownSport]

Not, ahem, very good at emissions-
Seems the PCV gets me about every two years; I think spring rusts and it sucks too much.
Does an '00 have an EGR????
Otherwise, pull some hoses and see if IAC is functioning

Google:
(Jeep owner, P codes are for most part universal)

mine did this vaucuum lines on driverside in front of mastercylinder there is i think the evap valve and the vacuum lines cracked and that was my problem so check yours out there is a few 90 degree hoses to make sure there hooked up two hook to your intake manifold thats the other that was bad on mine one came disconnected.

[white98rt]

no egr, and the iac is the same as a 98-99, so i swapped one out from my car that i know functions. unless it's wiring to the iac. guess i could check that. thanks for the suggestions.

[UptownSport]

SYMPTOM
P1495-LEAK DETECTION PUMP SOLENOID CIRCUIT

WHEN MONITORED
Immediately after a cold start, with battery/ambient temperature between 4.4 °C (40 °F) . F and 32 °C (90 °F) . Coolant temperature within -12 °C (10 °F) of battery/ambient

SET CONDITION
The state of the solenoid circuit does not match the PCM's desired state.

POSSIBLE CAUSES
Wiring Harness Intermittent
Leak Detection Pump
Fused Ignition Switch Output
LDP Solenoid Control Circuit Shorted To Ground
LDP Solenoid Control Circuit Open
PCM

Leak Detection Pump System
The evaporative emission system is designed to prevent the escape of fuel vapors from the fuel system. Leaks in the system, even small ones, can allow fuel vapors to escape into the atmosphere. Government regulations require on-board testing to make sure that the evaporative (EVAP) system is functioning properly. The leak detection system tests for EVAP system leaks and blockage. It also performs self-diagnostics. During self-diagnostics, the Powertrain Control Module (PCM) first checks the Leak Detection Pump (LDP) for electrical and mechanical faults. If the first checks pass, the PCM then uses the LDP to seal the vent valve and pump air into the system to pressurize it. If a leak is present, the PCM will continue pumping the LDP to replace the air that leaks out. The PCM determines the size of the leak based on how fast/long it must pump the LDP as it tries to maintain pressure in the system.

[white98rt]

tried putting my hand over the throttle body where the air filter connects, and it didn't die. it made it actually run right. there must be a huge vacuum leak somewhere between the throttle body and head. thanks for that post about the jeep ted, made me think about trying that!

[white98rt]

throttle body is cracked, looks like the iac has been trying to get the idle speed down with the cracked tb, and that's what is causing the jumping. that was a head scratcher for me, thanks for all of the help and suggestions.

[UptownSport]

Glad you found it!!!
There's 2d gens at Rosemount- EZ fix.

How / why you think it cracked?????

[white98rt]

2000 is an orphan year. 95-99 used one tb, 01-05 used another. the 2000 tb uses the sensors that the 98&99 i have use. the only 2000 i have found in a junk yard had the throttle body removed. i think it was in a front end collision before i bought it. The hood is pretty gnarled up, that may be how/when it cracked.

[white98rt]

apparently it wasn't cracked. i thought the blade was cracked because it leaked air past. wasn't the problem. After taking it off completely and giving it a good look, i found someone decided it was a good idea to fuck around with the little stop screw, making it stop with the blade slightly open. Sometimes, i hate people.