1995 Chevy Tahoe 4X4 - Adventure Rig Build

Chevrolado

Cruisin'
So.. chasing my tail again on the bouncy idle that has resurfaced.
It doesnt ALWAYS do this. Only sometimes. Then I'll keep driving it.. then it will fix itself.
Then 1/2 mile later, when Im coming up to stop at a red light.. it starts doing it again.
Then drive further and it settles out again and idles fine. Then decides to idle funny. Then fine. Then funny.. Randomly.

This vid is this afternoon when I was parked somewhere. I started it up.. idling fine for about 3 seconds. Then it started bouncing. So I recorded it. Then I finally just said nevermind.. and drove away. Then it stopped doing it for about 10 minutes at red lights. Everything seemed fine. Then as I was coming to another stop light somewhere.. started doing it again...
http://youtu.be/84eqyZYXGTU
 

Rebelord

Semper Fi
Off and on like that. Hmm do you have a obd 2 scanner that you can read and see real time data?

Sent from my Moto X
 

Rebelord

Semper Fi
Ah. For some reason..I dont know what I was thinking. I know that.
Does it only do this after driving? Or can you replicate it on a cold start in the driveway?
If you can replicate it in your driveway. Then that makes it hopefully easier to diagnose. Check all your usuals. Vacuum lines, electrical connections etc. Eprom for ECM stock or a modified; like Jet?
 

Chevrolado

Cruisin'
Ah. For some reason..I dont know what I was thinking. I know that.
Does it only do this after driving? Or can you replicate it on a cold start in the driveway?
If you can replicate it in your driveway. Then that makes it hopefully easier to diagnose. Check all your usuals. Vacuum lines, electrical connections etc. Eprom for ECM stock or a modified; like Jet?
I cant replicate it every time. It's happening more frequently now. But not everytime. :(
The ECM is stock, however, it has a piggy-back chip that was designed and built by Edelbrock to match the Performer heads, Performer manifold, and Performer-Plus cam that I have in the motor. All Edelbrock gear. It's supposed to level out the ECM and control all the new things the same way the stock ECM controls the stock gear.
 

82fb

Adventurer
Loping idle sounds like a vacuum leak, and the computer is trying to compensate by adding some fuel, getting too much, then adjusting over and over. 95 is TBI, right? If so, the throttle bodies can wear our around the shafts and start leaking a bit of air.
 

Chevrolado

Cruisin'
Yeah,nice neighborhood and truck!
Thanks! :D

Loping idle sounds like a vacuum leak, and the computer is trying to compensate by adding some fuel, getting too much, then adjusting over and over. 95 is TBI, right? If so, the throttle bodies can wear our around the shafts and start leaking a bit of air.
Thanks.. I think I've figure it out. I disconnected my EGR valve to check and see if the EGR was stuck and it hasn't really been doing the bouncing idle much since and Ive been driving it for about a week now without any vacuum hose running to the EGR.
So I got a new EGR valve and a new MAP sensor (since the MAP is the original one from my old motor) and I plan to put them both on this weekend and hook up the vacuum hose back to the EGR. Then we'll see if my bouncing idle comes back or not. :)

For now... I'm just cruising it around town.

13953877336_41d41bd0df_c.jpg
 
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Chevrolado

Cruisin'
Thanks Chilli. :D I enjoy it.

As for an update, installed the new AC Delco EGR Valve, AC Delco MAP sensor, and removed, cleaned, and oiled my K&N to make sure I had fresh air flow as well. :)
Truck appears to be running pretty well now. No bouncing idle has returned yet (I installed everything on Friday evening and I drove it Sat, Sun, and now Mon). So I'll keep watching for it, but for now, it appears to be running decent.

Just rolled over 176k too.

14086094105_394c455af4_z.jpg
 
Last edited:

chilliwak

Expedition Leader
Thanks Chilli. :D I enjoy it.

As for an update, installed the new AC Delco EGR Valve, AC Delco MAP sensor, and removed, cleaned, and oiled my K&N to make sure I had fresh air flow as well. :)
Truck appears to be running pretty well now. No bouncing idle has returned yet (I installed everything on Friday evening and I drove it Sat, Sun, and now Mon). So I'll keep watching for it, but for now, it appears to be running decent.

Just rolled over 176k too.

14086094105_3f278bc220_z.jpg

All I can say is `wicked ´ :wings:
 

Chevrolado

Cruisin'
Thanks Chilli..
So far this week, all good. Still running strong. No bouncing idle has returned.
That being said, filled up the gas tank last night. Ouch. $$$ :( hah.

Hopefully now with a decent running EGR valve, I'll see a little better consumption on this tank.
 

justcuz

Explorer
I was going to say EGR valve. Check your EGR solenoid too. These have a negative pressure EGR valve. If the can does not have an N stamped in it next to the part number it will run worse with the new one. The generic auto parts store ones suck! I buy mine now from Rock Auto online. They have the right ones.
 

Chevrolado

Cruisin'
I was going to say EGR valve. Check your EGR solenoid too. These have a negative pressure EGR valve. If the can does not have an N stamped in it next to the part number it will run worse with the new one. The generic auto parts store ones suck! I buy mine now from Rock Auto online. They have the right ones.

Thanks for the info. Yes, I had a new generic one on the new motor when I put it in. I got this new one from Rock Auto as well once I pulled the proper part number from the dealership (they wanted my VIN to make sure they got the exact correct EGR for my truck).

It appears to still be running fairly well. :)
 

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