01 QX4 stalling when i stop

[chicoson]

for some reason my 01 QX4 has been stumbling then stalling out when i come to a stop. it stalls about 3 out of 5 times. i have done all tune up stuff like plugs,coil packs,fuel filter,air filter. it does not seem to stall out as much when it is cooler outside. more less when its hot and humid. i was thinking IAC valve or a barometric temp sensor (not sure if they have them) there are no codes or engine light on. anyone have any ideas? i think im gonna seafoam it and see what happens. always fun to see smoke hahaha.

[asnorton44]

Sounds like your MAF.

[chicoson]

nope! replaced that with a new one 2 months ago. i guess there is a chance it could be bad again. it feels like a bad IAC valve. when the engine is cold its fine but when it warms up it wants to stall with my foot on the brake.

[Pathy415]

vacuum leak somewhere?

[chicoson]

cant find a leak and all my lines are good. not rotted or anything. do these have a barometric temp sensor or anything? it started when the weather here in michigan got more humid and hot.

[ARKQX33V6]

Idle air adjust, run a raw propane tank open over the engine bay when it does idle looking for an increase in idle RPM.

When warm and idling do you have to keep foot on throttle if yes check throttle plate for idle position. Sounds like it needs more air

[chicoson]

yeah idle seems too low like 500-600 rpms so maybe i need to adjust the cable. im also going to do the seafoam treatment thru the vac system. i heard nothing but good stuff about the seafoam treatments. i removed the IAC valve and it seems clean and fine.

[ARKQX33V6]

Check EGR

[ARKQX33V6]

Careful with Seafoam, if you dump too much you will have all that carbon deposits to deal with, better a little for a long time than a lot at once. Dump 1/2 a bottle in a full tank.

[chicoson]

if it was the EGR i would think it would throw a code or engine light. i dont have anything or any CELs. i was going to do the seafoam in the intake thru a VAC line. bottle says it helps hesitation and idle thru the intake. i have marvels oil for the engine and fuel. i guess the old guys swear by both. im a bit skeptical after ruining my MAFS with MAFS cleaner. i have gotten a new one since then.

[CanuckQx4]

Idle air adjust, run a raw propane tank open over the engine bay when it does idle looking for an increase in idle RPM.

How do you "point" where the propane goes??? Some kinda hose attachment?

[ARKQX33V6]

No with propane it is heavier than air. Turn the valve on dump the propane and put the nozzle as close as you can get to the group of vacuum lines. The vacuum will suck it in, and the idle will rise. If you get any rise in RPM with an open propane battle you have a leak.

Now to find that leak. By careful and concentrated effort. Feel look at each line, each connection. Is a hose brittle, hot, burned, cracked, spotty or breaking apart as you touch it.

Propane, natural gas or methane, butane can all be used but use extreme caution, these gases when mixed with air are very volatile and use with good ventilation. Usually when used as a combustible source they will only burn and not explode since you are using the gas in an open area, not enclosed. Gas in enclosed area plus ignition blow up.

Other gas than propane are lighter than air. So placing your nozzle to wrap that gas into a vacuum line can be critical.