Hey all,


So my idle is being really random lately. Or at least i can tell now. Recently i put a set of DT Headers on. Went well i thought. Then i got a new intake knock off K&N style intake because my old intake hose had a crack in it that was letting air in.
Ever since then, iv noticed what i assume is my EGR (since i can now hear it making a bap bap bap bap noise at idle around 1k rpm when cold because it goes straight into my intake pipe instead of the old silencer box)

My questions are:

1. the Bap bap bap bap noise i hear around 1k-1200 rpm is my EGR opened right? My searching leads me to believe this. Kind of sounds like a jake brake only a little slower. When i rev it shuts off and goes silent, or when it drops to around 900 or less rpm it also goes silent. and when i pinch that bigger tube going to my intake, it also gets quiet

2. My other thoughts now are my TPS? or maybe even my thermostat?

Symptoms:

I start it up cold. Idles around 1300. Notices it can go as high as 1500 at stop signs when still cold. I get on the freeway and warm it up. Coming to a stop after prolonged freeway speed it will idle around 1k. If i sit and let it idle long enough, maybe 5-10 minutes it will eventually drop down to around 700rpm (where i have set my idle numerous times now when warm) while still hot. (when i hit traffic real bad on the bay bridge) But if i pick up speed again for a short while and then stop again, back up to 1k ish idle.

Since i can now hear what i think is the EGR, and it annoys the ˟˟˟˟ out of me, when its warmed up and im stuck at a stop light i can hold on the brake, and let the clutch out slow, dropping my rpm down to below 1k, and it will stay around 8-900 after i push back in the clutch! how? But if i blip the throttle, it will settle higher than it just was.


Thanks for taking a look

 

Are you getting the rpm's off of a factory tach or an aftermarket one?

 

factory

 

I would verify that the idle is actually surging by hooking up an aftermarket tach to the engine, seeing as factory tach's aren't renowned for their accuracy. Also, check if the throttle is sticking a little bit as it could cause the same issue. How old is the O2 sensor?

 

you know, the O2 sensor is.. i have no idea how old. I am betting its original. Iv never replaced it, had the truck for around 8 years. Bout to hit 200k miles.

As for the idle, im positive that the engine is actually changing RPMs. Your right it might not be 100% accurate but i can tell how my truck sounds at different RPMs and its pretty clear that its idling higher/lower. Also the opening/closing of my EGR is in correlation to the RPM change when no throttle is being applied. If i had a aftermarket tach i would try this just to rule it out tho!

 

I would replace the O2 sensor with a new Denso one, and possibly the EGR with a good used one. I would tell you to just get rid of the EGR, but seeing as you live in Commyfornia that isn't an option.

 

Yea im getting a little tired of california. Sales Tax is gonna be 10% any minute now too. bah.

What store online would you get it from? or just pick it up at an auto parts store? Trying to find one right now online.

 

I don't have any particular store preference, but I just found multiple matches online for a Denso O2 sensor http://www.google.com/#q=3vze+denso+...2370386c77b788
Although if you can find it locally it will be a lot quicker than having to have it shipped. I also forgot something; seeing as you are in California, your truck has two O2 sensors! One before the cat and one after, and they are not cheap

 

Hey guys,

I have the same idle issue but my engine is fully stock. When I'm in stop and go traffic, my idle drops to about 500rpms and the engine begins to stumble and surge. If I don't rev the engine, the engine dies. But when I'm just puttin' down the roadway or I stop every so often at lights and stop signs, the beast runs fine.

Before I begin replacing the O2 sensor and EGR, I'd like your guys advice. PLEASE! I'm about a gas tank away from taking a sledge hammer to my engine. Hahah!