Stalls at idle, vacuum leak?
 

2007. 65k miles, original engine, maintained very well.

Car will stall out while idling, red lights, stop and go traffic. RPM jumps from 800-1200 . I can prevent this by keeping the revs up. I don't feel comfortable using this as my daily driver anymore until i fix this problem. From what I understand it could be a vacuum leak? I thought I would ask here for any advise.

Thanks

Could be a lot of things. Did it start suddenly?

Do you have an OBD2 reader that you can pull fuel trims and other data off?

Compression? Does it warm start OK?

No OB2 reader, It must've stalled out a dozen times when I was driving it home, it starts perfectly, hot or cold.

Yes the problem did start suddenly. I've had no major problems with the car since new, replaced the coolant bottle, that's about it

I don't think its a compression issue, the car starts and drives like normal, it still pulls strong. It sounds like the car is choking at idle

Could it be my clutch is going out? its still the factory clutch, and I learned how to drive manual on it.

Fuel issue makes sense as well.

Thanks

An OBD reader would really help here. If you can monitor what thr compute is seeing, you can save a lot of guesswork. There are Bluetooth ones on ebay for not expensive at all.

Yes it could be a vacuum leak, that would be my first guess too. Check over all the little hoses, especially the VFAD line. It was supposed to have been plugged when your intake was installed, maybe it came unplugged.

check the throttle body. the butterfly valve could be contaminated by gunks.

It could be a s simple as a slight vacuum leak or as serious as low compression but the fact that it starts when hot is good. You really just need to trouble shoot it, check for cracked or disconnected vacuum lines.


Go to engine ----> symptom troubleshooting

http://foxed.ca/rx7manual/2003mazdarx8/

Doesn't a small vacuum leak increase the idle RPM? I read on this club that a tiny leak would actually increase the RPM, not decrease :dunno:

Nope. If it's detected, the ECU will try and compensate but most go undetected with no CEL in my experience. But that is why I love my smoke leak detector, it is a great tool.

Keeping the Engine at an Idle
• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Mass Air Flow Sensor (MAF)
• Front O2 sensor
• Catalytic Converter (Cat)
• Intake Vaccum

Thanks for all the help everyone, I fixed the problem. It was the racing beat intake, the aluminum part came loose from the air box.

Hello I'm having a similar problem, but not exactly. My radiator fan took a chunk out of the hose that connects the vfad solenoid to the vacuum chamber. Would this cause a vacuum leak serious enough to cause my car to die at idle? Moving or sitting still? It runs fine as long as i keep the rpms up. I also have the racing beat revi intake. So should I even still have this vfad line? Or should it be plugged?

It should be plugged, this is part of Racing Beat's installation instructions.
As for whether it can cause stalling... it can, but my question then is was it plugged before and the fan opened it up, or it was always open and something else is causing the problem?

The guy i bought the car from 3 years ago installed the intake. He did not disconnect the vfad and plug the hole. It is all still connected. The fan opened the line up, but I'm not 100% sure it's the culprit. I'm just checking to see if it's a possible culprit. I should also note that I was having misfires and serious power loss which caused me to change the coils, wires, and plugs. Power came back in full effect. If I rev the car up past 4k rpm it WILL die if I let it immediately drop back to idle. At 4k it's hit or miss whether it will die or catch. If it catches, then it does so ~700 rpm then slowly works its way back up to ~850-900. But as long as I don't touch anything it will sit there and idle perfectly. No hiccups or backfires. It used to catch around 1.2k rpm and then slowly work its way down to ~850-900 prior to all these problems. I did the fuel trim reset (although I may need to do it again and try a different learning method. I just drove ti). Double checked plugs and wires and their respective connections to the coils. Everything is right.

Update: Check engine light came on while driving. Have a p0302 and p0443 (this was already there). So I guess i need to triple check the rear hah.