I got a 96 dodge neon that has a idling problem. It wont idle blow 1100 rpm’s. Sometimes during driving the car will rev higher and will accelerate itself up to 55mph. I can come to a stop and hold the brake peddle and tap the gas peddle and it will come down. I have checked for vacuum leaks and replaced idle air control valve 4 times. Running out of ideas what could cause it.
Sticking throttle cable or throttle plate. Use Throttle Body Cleaner to clean the throttle bore and throttle plate. This procedure is so simple, even a caveman could do it.
Yeah, clean the throttle body and check to see if the PCV valve is stuck open or sticking.
Had pulled the throttle body off to replace the IAC and cleaned it then with a new gasket. Replaced the PCV valve also. Checked the Throttle cable also and still nothing. Replaced the EGR valve and the tube and the grommet that goes into the side of the intake manifold
So there’s more that’s been done other than vacuum leaks and IAC. Anything else you want to add before people spend their time for you to later provide info they needed to start with?
How did you check for vacuum leaks? If it is anything other than a vacuum gauge just get one and use it. Lots of people “check for vacuum leaks” - unless they are glaringly obvious few people find them when they are there.
Check the throttle position sensor with a multimeter - voltage supply & correct operation. Do the same multimeter work with the power supply to the IAC. The electrical specs for these things should be in a repair manual if you have one.
Clean the MAF.
Sorry been trying to keep these short. Yes used a vacuum tester and have a Snap on Scanner also. Tested the TPS and that is ok. Car has no MAF and double checked with the dealership and 2 parts stores.
This could be a bad electrical connection at the battery at the main fuse box,or ground. Check condition of battery cables
Your ECM reads battery voltage, and if voltage is low it will raise idle to the amount you described in a attempt to keep the battery charged.
with every accessory turned off will it idle low? and start idling high if you turn on the headlights or rear defroster?
Do you have a meter to read voltage at main fuse box and battery to check for a voltage drop?
If You pull the plug on the IAC and turn the car on and idle is low then the car is raising the idle for a reason.
Do not know if a defective MAP sensor could cause the problem. This is what the car uses to measure air volume going into the engine.
Have you checked for any stored trouble codes?
Since you seem to like to provide info only when directly asked I’ll just ask. Are there any OBDII codes stored in there?
With no MAF then air metering info probably comes from the MAP - clean and check that (but I suppose you probably did already). Check coolant temp sensor and air temp sensors (but I suppose you did that already too). All of that, of course, has to do with stuff about the ECU and air/fuel mix and what can throw it off. In the end, I suspect that you’ll actually need to revisit the mechanical linkages - throttle pedal/cable, plate, return spring, etc.
Just Cleaned the battery cables and replaced the battery with a new alt., bearings went out in it. Have a Snapon Scanner and checked for codes and with it running checked voltage read out at the ECM and its battery voltage, 14.4 with the engine running. Tried the unpluging the IAC and running then engine and With it warm it still idles the same. With the Snap on Scanner controlling the IAC and cant get it to idle low but can raise the idle. Did Check the MAP and its good. Thanks for the feed backs.
Sorry for the inconvenience that i am causing you, its hard to recall everything i have done to try solve the problem with this car all at once. I have had the throttle body off the car and checked it all out after cleaning it completely. Had all the cables disconnected and checked them all out. I checked the MAP out and Checked it with my scanner and it is fine. No codes at all… Temp sensors are ok and With the scanner on it it i can’t see anything out of norm.
Still possible air leak at manifold.
I still own a 95 Stratus with 2.0 SOHC engine. I know that pulling the throttle body removing the fuel rail and removing the intake manifold takes about 15 min. I would remove it inspect the plastic manifold for cracks, and replace all the rubber gaskets, and Fuel injector O rings. If you have a plastic oil separator below the intake for the EGR it would be a good time to remove it. clean it out and replace the two drain back rubber hoses, Not sure the year this engine have the oil separator.
I have thought about going that far, and seams like i need to Thank you and from what i see i don’t see a oil separator but the one thing that is odd is the fact they would run the pcv valve off a direct vacuum port off the intake almost causing a constant vacuum leak anyways with even a new valve in the system.
Go to the dealer. Have them set the idle with the DRBII scanner. You’ve done everything else short of ordering a crate engine.
If they can’t set the idle (yes, they can do this to any rpm you please), then it’s still beyond the range of the IAC’s ability to compensate for …and you’re back to looking for the vacuum leak.
“It won’t idle below 1100’s.” Pull the black plastic (rubber?) intake tube. Carefully inspect it for splits. Make sure that the intake tube seals well at either end, when installed. Disconnect the brake vacuum hose, and cruise control vacuum, and plug the ports (temporarily). Temporarily, plug any other vacuum sources, if they don’t interfere with engine operation.
Disconnect the throttle cable at the throttle body. Actuate the throttle plate, numerous times, and see if the throttle plate returns to the idle stop, smoothly. Hold the end of the throttle cable, have an assistance press and release the gas pedal (numerous times), while you keep light tension on the cable. Does the throttle cable move smoothly, and return (when pulled with a light pull) to the stop at either end?
I will be taking off the intake going through everything, looking for cracks. But disconnecting everything that uses vacuum and running the engine with all the cables off the throttle will be the first thing i do. Have had the car for 5 years and it just started this 2 years ago when the car got 170000 miles on it. It now has 197000 miles on it. Tried most of it 2 years ago when i replaced the IAC for the 4th time but maybe things might have change seance then.
My 95 Stratus got 170,000 miles on it. and still has a cold A/C!
Mine has a leak on the upper hose to the condenser core. Got to put 2 cans in it every summer to use it.