My truck has about 50,000 miles on it. It has always ran smooth and well. The past 2000 miles or so, I noticed that when idle, or sitting at a red light, the truck would sometimes drop its rpms suddenly, and start to get rough, as if it was about to stall out. It drops to about 450 rpms. When it happens, I tap the gas for a second and it usually clears up long enough for me to continue driving and forget about it for the day.

Is there somthing I need to replace at 50k miles? I did plugs at 35k, so those should be fine. Is there some sort of EGR or vacuum valve that needs to be replaced?

I did one on my wifes car when hers started to idle funny a few years ago, it was a 50 cent fix.

Anyone know?

 

Sounds more like a PVC valve issues, they are cheap and should be checked 50 to 60,000 miles. Don't buy a universal one, this is one of those things that i would go to the dealership for.

When your engine started to rough idle did it throw any code?

I replaced my EGR valve at 50,000 because the sensor went bad. The EGR was still functioning and didn't cause a rough idle. But a clogged EGR valve can cause a rough idle. FYI.. the EGR is a son of a bitch to change, but is possible if you have enough extensions and u-joints.

 

Would this hurt your gas mileage if not fixed? would it end up throwing a code at some point?

 

I see PVC valves for the truck are $4. I will start there. Its really not a big problem, no codes, and it hasnt stalled yet. I just noticed its starting to happen.

 

I'm not sure if the PCV valve will throw a code or not I assume it would.

A clogged EGR or a EGR with a bad sensor will ruin your gas millage and either will throw a code. When my Sensor failed my gas went down about 3-4 mpg.

 

Ok. Im definately not experiencing any mpg loss, or codes, its just an occasional idle issue as describled. I'll start with the PVC and post my results.

 

when my 2005 started to do that, i had to switch out the throttle positoning sensor, simple replacement on the throttle body, cant remember the price but it was under 100.00 i think

 

oh ok I will keep that part in mind as well.

Thanks.

 

Another thing.. when was the last time you cleaned your throttle body? Its as simple as pulling off the Air box that attached to the TB. and get some TB cleaner. Also pick up some lent free shop paper towels, to wipe and clean any excess cleaner and residue. I personally do this twice a year. Your engine might not want to turn over at first and some white/blue smoke might come out of the exhaust.

 

I would definitely look to vacuum-related parts first. When I yanked the brake booster line to suck down some SeaFoam, the engine almost quit. Shook and stuttered before recovering.