Car stalls/dies out when I go in neutral sometimes why? Help

[bobbystang]

Guys, this is happened A few times over the past couple of years and when I drive my car Im always driving cautiously to prevent this from happening. I don't want to drive my car scared, but when I drive it and am downshifting and the RPMs are high and I just randomly throw it in neutral and keep it there the car will stall and turn off or even at normal speed as I'm downshifting from say 4th to 3rd gear in between that gear RPMs will be high or wherever really and it will just die out only when I keep it in neutral his happens. I really really want to get this fixed so I don't want to drive my car scared! Please help with advice. Thank you

 

[01yellercobra]

It's probably the IAC acting up. You can try cleaning it and seeing if it gets better. If it does then I'd replace it with a new Motorcraft unit.

 

[bobbystang]

Do you think? I took the OEM one off many years ago and I still have it and I put one on from AutoZone and I just cleaned that one with throttlebody cleaner and Q-tips this weekend. The original OEM one I took off I never attempted to clean and you think I should maybe put the OEM back on and clean it off and put it on?

 

[98_Undertaker]

I chased a similar problem for over a year, I changed the IAC, cleaned the MAF a few times, cop's, plugs, and the tps with no luck at all. I finally decided to take a swing and shut the EGR off and it solved mine.

It may be the IAC or it could be a lot of other things.

 

[josephcostello]

Agree with checking the IAC, I bought one from Oreilly for $40 for my '01.

 

[bobbystang]

Thanks guys and I put my OEM IAC back on and cleaned it and I drove it today and things seem to be good with throwing it in neutral after my RPMs are high I need to drive it a few more days and try at higher speeds and then drop it out and make sure nobody's behind me in case it does shut off. And I looked up those EGR valve delete kits and obviously it's cheap but what does an EGR valve do that exactly causes this on our cars to shut down?also just curious what potential harmful things can happen with deleting your EGR? Thanks

 

[josephcostello]

The egr valve to my knowledge causes the idle to hold at 1,100 or so and then drop to normal when throwing the car in neutral. This I think is just for smog reasons and is normal. I believe I found a couple fourms on this site of people doing a certain mod like you're talking about where it will drop straight to idle. No idea about removing it but I don't think that would fix the problem of the car shutting off it would just make the car drop straight to normal rpms. I had the same problem as you, where the car would hold rpms in between shifts and when thrown in neutral would either stay the same or in my case rise to like 2,800 rpm and then drop after like 10-15 sec. I cleaned my iac after seeing it was filthy and it did nothing, but it did work because I unplugged it when the car was at idle and it bogged down and ran shitty as expected. I swapped it for a new one and it worked fine for a week until yesterday it started doing it again. Will be looking more closely for possible vaccunm leaks if it keeps up. Also, wouldn't hurt buying a new pcv valve (located on drivers side valve cover gasket closest to firewall) they're like $2 at Oreilly for 99-01s. Hope at least some of this helped, hope you get it all straightened out.

 

[01yellercobra]

The EGR is to increase mpg while cruising. I know it's inactive at WOT. I'm pretty sure it's inactive at idle. Don't quote me on that though. I know on my 01 it caused a surging at part throttle. I didn't feel like dealing with it so I deleted it.

If you want to to delete it you need to have it turned off in the tune as well. Otherwise the car won't run right and you'll have a constant CEL.

 

[po-po 5.0]

EGR stands for exhaust gas recirculation. That's literally what it does: allow a little bit of exhaust back into the intake, but it's only supposed to be open at cruising speeds. If that valve hangs open for whatever reason, it could cause some weird idle conditions as it's supposed to be closed, and the ECU isn't compensating for the extra "air." The more common cause is the IAC, and I second what other's have said: replace it with a MOTORCRAFT one. The BW/Wagner/Bosch ones that the parts counter sells you for cheap seem to die early...if they ever work right at all.

 

[STAMPEDE3]

When coasting in neutral or the clutch pressed and over 3mph the idle goes up on purpose to help with braking since the hydroboost is run from the power steering pump. That is 100% normal.

The stalling is normally IAC related but sometimes doesn't go away.
If you have a tune your tuner can make some dashpot setting adjustments to help I think.

 

[bobbystang]

Yup I put the stock iac back on and drove around and seems to be good again but I need to do further "throw in neutral at high rpms testing" and see if it stays on or stalls but so far so good on my initial few drives.