mr spree

iTrader: (4)

Oh okay, is there a cheap one i could buy or ill just have to take it to a tuner shop or something

Hasstle95Z

Check for a vacuum leak.. and make sure the ducting to the throttle body is tight I doubt its the 02's if they were that bad youd have a heater code or rich and lean code

mr spree

iTrader: (4)

Whats the best way to check for a vacuum leak? Or where to find out where its coming from.

I have a suspicion its coming from the rear of the truck intake (LQ4 Motor). Theres that part on the back of the truck intake im using for my brake booster, but idk where to buy a plastic piece that fits into that to hook a hose up to it, so i found a small metal pipe that i fit into it and clamped a hose on it.

Anyone know where i could pick up a fitting for that hole on the back of the truck intake?

thanks

Hasstle95Z

I use a smoke machine you will find a vacuum leak every time. But i have access to one at my shop. Fix that metal pipe first see if it runs better if it does..problem solved if not find a shop to "smoke it"

mr spree

iTrader: (4)

Well do you know where i could find the actual piece that goes into that port in the back of the truck intake?

What kind of shop would do that?

Hasstle95Z

Ive never replaced that part so i don't know.. If the part is oem try the gm dealer.

Most good shops should have a smoke machine if they don't i would wonder about them

98Z28CobraKiller

iTrader: (17)

You can just spray carb cleaner or brake cleaner on it and see if the idle changes. It sounds like a vacuum related problem for sure. You are either bypassing the MAF with unmetered air or the MAP sensor is taking a crap on you.

BaddBird

iTrader: (6)

If this was a vacuum issue it would also do it when it was cold.

Hasstle95Z

Not necessarily the pcm is dumping a lot of fuel in open loop

BaddBird

iTrader: (6)

Its not dumping enough to cover up his problem. Besides dont you think he would be tripping a lean code.

mr spree

iTrader: (4)

well this morning it was about 40 degrees, cold start and gave it some gas on my way to work and sure enough it did the same thing, falls on its face. So ill try spraying carb cleaner to find the issue

So a vacuum leak would cause my truck to idle up and stay at 2000 or 1500 rpm by itself when just touching the gas barely?

BaddBird

iTrader: (6)

Man your kinda of all over the place with you description dont you think?. Find and fix your vacuum leak.

mr spree

iTrader: (4)

Yea i know, the first couple days i had no problem, but now its doing it all the time

mr spree

iTrader: (4)

sprayed carb cleaner on all the vacuum hoses and what not and the idle didnt change.
Maybe i just need a tune?
Would the IAC cause a problem like this?

Hasstle95Z

he says there's a vacuum leak in the back of the intake. He should just fix that regardless if thats the problem

jp92z28

iTrader: (8)

Did u check fuel psi at idle or under a load(full power)? Need to check it while driving it. Have u checked ur fuel filter?

Truck intakes are bad about the intake gaskets leaking causing a vaccum leak. Normally this shows up when they are cold and after the engine warms up it seals the leak but urs is doing the opposite.

If u want to check ur cats then u need a back pressure gauge or remove the O2's and see if it runs better.

Have u cleaned ur mass air?

The o2 could be bad but at wot the pcm goes into open loop and rules that out.

let us know

youguessit

fix the vacum leak and start from there... could also be an exhaust leak... if it were fuel it would get better when the car got warm...sounds like o2 sensors, exhaust leak, vacum leak, or bad maf/ maf plug. The map sensors rarely go bad but its a possibility. car has to be running very lean to throw code for it. If it is falling on its face and it were do to it running lean it would throw the code for sure. Sounds like vacum leak to me but i havnt been there to see and hear the problem in person so its a guessing game.

mr spree

iTrader: (4)

Well i replaced the TPS sensor and she idles great now. No more Idle surges or anything.

Still having that huge power loss when i punch it. It runs great when i first start it up if it hasnt been running for awhile. So im guessing when it goes from Open loop to closed is when it falls on its face.

youguessit

dont know what brand tps sensor you got but put it on a live data monitoring system and put the pedal down slowly looking for irregularities. Nothing and i mean nothing works like ac delco.

t . b o z

I have a similar problem with my car.
Its got LT's, lid, and true duals, and every once in a while when I go WOT, it wont pull. The rpm's climb slowly, then kinda stop around 5000rpm(+/-). the car wont have power period...

However, it isnt dependent on engine temperature. I dont ever get on it when its bone cold, but when it isn't fully warm and I go 50-70% itll go kind of the same thing.

My car isn't tuned yet, so Im hoping its a tuning issue, but can anyone tell me if thats what it is for sure? I thought it was the damn transmission slipping, but I hooked up a TechII and it didnt show any trans slip codes....