stalling when outside temp is over 80 deg.

[DCobb]

Have a 97 Ranger xlt 4 cyl. auto 250000 miles. the truck does fine in mornings when tem is below 80 outside. but usually on the way home in the afternoon when its hotter out above 80 usually. it drives ok idles fine but once I get nearly home after average 20 plus miles in traffic it wants to stall when I stop at a light ot turn slowly but not at idle when I go to step on the gas it just dies and only does it when hot outside. no light comes on and has always restarted after a few tries but i get stuck usually in the worst possible place with no where to get out of the road and there is no other route to take home.
it did it last year but got cool so i thought pouring in all that fix it junk did it. now its back in the mid to high 80s here in central Florida and its acting up again. I had a code last year of p0420. and another but I dont remember which at the moment. the auto place wont read it now as I have no check engine light on ( i think it was clipped before i bought it)
anyhow before i start willy nilly replacing a ton of stuff maybe some one can help point me in the right direction. so far i checked all the vacuum lines and connections on all wirings ok and replaced the egr pressure feedback sensor as I had one. its running smoother but still stalling nearly every day on the way home. today after i stopped for gas i simply pulled to the side and sat there for a little qwhile. I also get a slight whif of exhaust smell before it starts acting up. could the CAT be doing this or an O2 sensor? any help would be appreciated. I looked onthe forum but didnt see anything exactly the same so decided to post here. thanks

 

[DCobb]

it only stalls when I go to take off otherwise its idling fine. it does sometimes sound a bit rougher but mostly just dies no bucking nothing.

 

[Mark_88]

My Tempo used to do this and every time it was the fuel pump...I say every time...as in 5 times I had to replace the in-tank pump...but there are things you can do to test fuel pressure...if you don't already have a gauge mounted somewhere...or haven't already done so...but Schrader valve comes to mind...you can use a vacuum gauge to read fuel pressure if needed...just a matter of where you hook it up...need a short rubber hose adapter usually.

But if the truck otherwise starts right up after it dies then I'd say it's probably something simpler...like maybe the fuel filter...

The codes can be checked on this site...p0420...comes up as catalyst system efficiency too low...or out of range...

http://www.therangerstation.com/tech_library/OBD-II_codes.shtml

Other than that...just keep an eye on it and if the frequency increases or CEL comes on again...check codes...

 

[DCobb]

Not saying it isnt the fuel pump but it only does it in the afternoon when I drive home so far. it never has did it in weather below 80 degrees. still going to change the fuel filter this weekend as changing oil and oil filter I like to do them both same time.changing the downstream O2 sensor too this week but waiting till payday like everyone else money very tight and reason why wanting to try to narrow it down more and not replace a bunch of stuff thats good. going to check on the fuel pressure guage as I got to get a code reader anyway as the parts store wont do a read out as the engine light never comes on not even when starting up. I think it was clipped before I bought it. or it was moved to the abs light as its always on. had a fuel pump problem on the old car but it did it all the time no pattern cool or hot. Im thinking also the EGR valve needs replaced also. or a good cleaning out. Im actually at a loss to what it is as there is a pattern here but does it randomly an no engine light. very stressful daily at work worrying about the drive home. I nearly got a ticket for blocking the intersection as the cop was really a jerk when I was simply trying to push it out the way for traffic to get by before trying to start it up again.

 

[Mark_88]

LOL...been there myself a few times...in the intersection pushing my vehicle out of the way...good thing Rangers and Tempos are fairly light because not once did anyone try to help me push...

I don't like the idea of throwing parts at a problem either...although I've done it on many vehicles before I learned to troubleshoot them better...with fuel injection it's always pretty simple, depending on the year of the Ranger...

I've heard of the IAC causing warm stalls, but that usually doesn't include immediate restarts...the unit has to cool down before it will start again. Fuel pumps on my Tempo would only act up in summer...especially after a fairly large temp swing...say 30* or more...like often happens in spring and fall.

I spoke with a Ford Tech on the phone when they warrantied my fifth one in five years (it didn't happen after the warranty expired though!) and they said there was a seal on the pumps that would go out causing the pump to not be able to draw fuel...I said it seemed strange that the seal always went at the same time of the year...I heard him shrug his shoulders before he advised me the warranty would cover it and to have a good day...

EDIT: The temp sensor might also be at play here, but I will let someone who understands that a bit more than I do chip in...the way the temp sensor interacts with the computer or something like that...

 

[tomw]

I would check that the MAF is clean if a 97 has one. The two wires can get a bit of 'stuff' on them and mis-report airflow, leading, usually, to hesitation and problems when you accelerate. You are possibly not in 'closed' or feedback mode when it is cold in the AM, but in the PM it's warm enough to go into closed loop. Open loop will feed more gas w/o asking... more or less.
I would also check that the IAC will bump the idle when it's cold, and if there's any problem, remove and clean it.
One last thing is the fuel pressure regulator is vacuum modulated, such that when you step on the gas, the intake vacuum drops, and the fuel pressure gets a bump. The computer depends on that bump to act as an accelerator pump and squirt just a bit more fuel when you accelerate. Check the fuel pressure, idling, and remove the vacuum line to see if the pressure bumps.
tom

 

[All Sick 96]

Check the module. I had a problem like this a long time ago when the car would get hot it would stall but if you cooled off the ignition control module it would stay running seems to me like you have an electrical problem in the module or ecu.