Help

[andrewg29]

Alright guys I've got a 2002 chevy tahoe with the z71 package. A couple of weeks ago I was at a stop sign and my car just stalled out of no where the radio stayed on the a/c stayed on but the car just randomly died. I didn't think anything of it because the truck started right back up. Then it got to where it would do it two or three times a day. So I read some forums and replaced the engine coolant sensor because it was broke, the tps, brand new plugs and wires, put seafoam in the brake Booster, and cleaned the hell out of the throttle body. Well it seemed to run perfect after I did all that about two weeks ago. Well Friday morning I woke up to go to school and it started doing it again and im completely stumped as to what it is. Any info is greatly appreciated!

 

[Physh1]

Did you try to pull codes? Did you clean your MAF? Clean/replace your PCV or check for vacuum leaks? What's your typical idle rpm?

Cameron

 

[andrewg29]

Did you try to pull codes? Did you clean your MAF? Clean/replace your PCV or check for vacuum leaks? What's your typical idle rpm?

Cameron

Yep tried to pull codes nothing came up. Cleaned the MAF about 6k miles ago. I know for a fact it's not a vacuum leak. What is a pcv lol. when in Park the truck idles around 500rpm when it shift into drive it drops to about 300 or 400 then just randomly dies before I get out of my drive way. If I catch that it's about to stall I normally put the pedal to the floor it hooks and continues to drive fine then when it get to normal operating temp you would never know anything is wrong with it. I ordered a fuel pressure Guage off Amazon that will be here Tuesday hopefully it's something stupid

 

[Physh1]

Well, your idle is low. Mine fluctuates around 680-720 rpm. Yours is way low & it's why you're engine is dying. You'll have to do some troubleshooting but here are a few things to try.

MAP sensor...it's on the top of your intake manifold. If it's outta whack it can cause idle issue but this usually throws a code...google it or watch this.... You may just be able to disconnect the wiring from it...if nothing changes than it may be bad. If you have a vacuum pump/voltmeter you can test it via the method in the vid.

Take carb cleaner & spray it around the intake manifold where it mates to the heads with the engine running. If your idle pops up than you may have a common intake gasket leak. This is not a strong leak...just enough to fuss with little things like idle quality.

PCV is a crankcase ventilation valve...located on the back of the driver side valve cover. It's designed to burn oil vapors that build up in the crankcase. If this is dirty/clogged/bad it'll cause the engine to consume good amounts of oil instead of just vapors & dirty up your throttle body. Search it here...pretty common issue.

Based on your throttle body cleaning working for 2 weeks than the issue popping up again I'm leaning towards a PCV issue...id start there.

Cameron

 

[electro]

All what Cameron said plus just put a new PCV valve in. They are included in the maintenance schedule. It's likely over due.

IAC valve. Idle air control. Two torx screws and an electrical connector to remove it, quite simple. Clean it with a tooth brush and carb cleaner. Should help. A new one couldn't hurt either. But cleaning is a good idea! It's a small pintle valve sliding in and out allowing air to pass by. Therefore controlling idle with how much air it lets go by or doesn't.


Sent from my iPad using Tapatalk

---------- Post added at 01:01 AM ---------- Previous post was at 01:00 AM ----------

And also keeping the throttle body clean at the butterfly valve is key. Carb cleaner and tooth brush.


Sent from my iPad using Tapatalk

---------- Post added at 01:04 AM ---------- Previous post was at 01:01 AM ----------

Your fuel pressure is likely fine. But no denying that's a great tool to have. Easy to use on our trucks that's for sure. Low pressure can indicate a weak fuel pump or clogged filter among a few other things.


Sent from my iPad using Tapatalk

 

[andrewg29]

All what Cameron said plus just put a new PCV valve in. They are included in the maintenance schedule. It's likely over due.

IAC valve. Idle air control. Two torx screws and an electrical connector to remove it, quite simple. Clean it with a tooth brush and carb cleaner. Should help. A new one couldn't hurt either. But cleaning is a good idea! It's a small pintle valve sliding in and out allowing air to pass by. Therefore controlling idle with how much air it lets go by or doesn't.


Sent from my iPad using Tapatalk

---------- Post added at 01:01 AM ---------- Previous post was at 01:00 AM ----------

And also keeping the throttle body clean at the butterfly valve is key. Carb cleaner and tooth brush.


Sent from my iPad using Tapatalk

---------- Post added at 01:04 AM ---------- Previous post was at 01:01 AM ----------

Your fuel pressure is likely fine. But no denying that's a great tool to have. Easy to use on our trucks that's for sure. Low pressure can indicate a weak fuel pump or clogged filter among a few other things.


Sent from my iPad using Tapatalk

I cleaned the Iac last night and my dad came and picked the truck up and is letting me drive his 09 z71 tahoe and he is gonna change the spark plugs to ac delco double platinum and gap them at .40 and I hope to God that helps cause I'm lost. And if the pcv valve was bad wouldn't the truck be consuming a good bit of oil? I changed the oil about 4,800miles ago and the oil dip stick is still on full.