Truck stalls when coming to a stop & severity of gasket leaks.

Joined
Jan 18, 2003
Messages
320
Location
Dallas, TX
My pickup (05 Dakota) will occasionally stall when I come to a stop after driving at a moderate or faster speed. More frequently it'll have a low idle for a second or two but not actually stall. What might cause this? Do far mecha haven't spotted anything obvious - they're saying plug replacement and intake system flush might cure it.

While in the shop, they're telling me that I have a leaky oil pan gasket, even though it's not enough to actually spot the concrete, even when I haven't driven it for weeks. Seems like a bit of an upsell to me. Same thing for the tiny drip they show on the auto trans output shaft - fluid level never changes.

Am I being too skeptical or am I right in thinking that these leaks aren't worth fixing on a 17 year old pickup?
 
The oil leaks are not causing the issue. as long as the leaks are soaking rubber parts like bushings or mounts you can live with if you want, you may want to look at the trans mount though, if soaked in oil replace it and fix the seal leak it is an easy job.
The stalling could be a vacuum leak from a cracked or broken vacuum/pcv hose, check all hoses and connections. Clean the throttle body and idle control valve on the throttle body which you will have to remove to clean.
Any CEL or codes?
 
What engine is your Dakota? If you have the 4.7 litre, good plugs are indeed important. Don't bother upgrading to anything beyond the stock plugs, as they work great. Also check for vacuum leaks around the intake to make sure it is not warped.
 
The oil leaks are not causing the issue. as long as the leaks are soaking rubber parts like bushings or mounts you can live with if you want, you may want to look at the trans mount though, if soaked in oil replace it and fix the seal leak it is an easy job.
The stalling could be a vacuum leak from a cracked or broken vacuum/pcv hose, check all hoses and connections. Clean the throttle body and idle control valve on the throttle body which you will have to remove to clean.
Any CEL or codes?
No codes or CEL.
 
Does that engine have an IACV (idle air control valve)? When my old Subaru developed that same symptom, it was caused by a failed IACV. The throttle was mechanical, and worked fine when driving. But when you idle, it relies on the IACV to control airflow to the engine.
PS: IACVs are expensive, so I tried several cheaper things first - plugs, timing, crankshaft & camshaft position sensors, etc.
 
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Surprised it has an iacv. My 2008 3.7 just had an electronic TB. First, clean out the iacv and any ports in it. 2nd, look for vacuum leaks, as someone else mentioned above.
 
intake leak, small one. which means gaskets at intake to cylinder head, gaskets in intake tract.
You can check the hose to power brake booster, & if the booster itself holds vacuum. (meaning you have a pump or two of power brakes with the engine off, the booster holds a reserve vacuum after the engine shuts down, there's a check valve to help hold that vacuum)
 
Throttle position sensors are super prone to failure on these. Wiggle test the plug at the TP sensor while it's running and see if the rpm changes or it tries to die; if it does it's likely bad. Otherwise your only real course of action is pulling codes and monitoring data when it acts up. As far as your leaks, we see stuff in the shop every day with minor to moderate seepage or leakage. Just because whatever is leaking isn't hitting the ground doesn't mean it isn't leaking, but it's still my job to pass on the message. Often the tech will explain to the service advisor that whatever is going on is minor and not a huge issue, only to be filtered through a salesperson with a manager whining to them about numbers and explained to the customer as "your car needs X". Also, more often than not folks want minor stuff repaired before it becomes major.
 
Had the same issue with a 2000 Dakota with the V6 and it ended up being the crankshaft position sensor. Yeah when it finally went out I was stuck on the road and needed a tow. Scanner didn't pick up any codes, but doing the Dodge thing where you look at the odometer after turning it on an off 3 times showed a code.
 
What tool did you use to scan the engine computer for codes? This sounds like a vacuum leak.
 
What tool did you use to scan the engine computer for codes? This sounds like a vacuum leak.
I don't know what they used, but it's a professional shop with a great reputation, so I doubt it was a $12 bluetooth dongle or anything like that.

They said no codes and they couldn't get it to do it or even to get it to idle funny. They suggested a throttle body/intake/fuel system cleaning and new plugs, which sounded like a good idea (never had the former done in 17 years, and changed the plugs about 70k ago with iridium plugs, so probably due).

I pick it up today... I'm going to keep an eye on it and see what happens. When I refused the leak fixes, they didn't seem concerned- I really do think they were trying to upsell me a bit, and not pointing out something that is actually problematic. My hope is that I'll get a new vehicle before those leaks become a real issue.
 
What engine is your Dakota? If you have the 4.7 litre, good plugs are indeed important. Don't bother upgrading to anything beyond the stock plugs, as they work great. Also check for vacuum leaks around the intake to make sure it is not warped.
Turned out that between new plugs and some kind of intake cleaning, it cured that weird stalling right up.
 
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