nubuilder
Why buy new when you can restore?
For about the past 2 months, my S10 has been acting up in terms of idling. Shortly after I bought the truck, I cleaned the TB and MAF (both off of the truck). When I did the TB, I put a new gasket on since I already had everything off. I don't know if this could have attributed to the idle problem or not, but wanted to make it known. About 2 weeks ago I replaced the IAC (figuring that it might be bad after 172k). That didn't seem to solve the problem. Last week I replaced the TPS. It is a little better and does occasionally idle down.
I'll try to explain what it is doing now.
When I push in the clutch and let off the gas, it surges up about 200rpm almost every time. It always idles back down once I come to a stop, but can take 2 - 3 seconds to start idling down. When I take my foot off the gas with the clutch still engaged (or out), it doesn't always start slowing itself down. When I push the clutch in, sometimes it will hang between 1700 and 2000 rpm. It can still pull itself down the road at 30mph in 3rd and actually pick up speed (since 28-30mph = 1800-2000rpm). If I keep the clutch out until the engine gets down to around 1000, it will stay there and not rev back up
Tonight when I got home, I experimented a little bit with the IAC, TPS, and MAP. With either the TPS or MAP unplugged, the it would idle down, but then it would hunt between 600 and 900 rpm. From this observation, I believe the MAP is still just fine. And with the IAC unplugged, it revs uncontrollably like there is a huge air leak (gee, I wonder why!).
I've read on other forums regarding the 4.3L and the 5.0/5.7L:
1) some guys try replacing the coolant temperature sensor. I might try this next as it is only $14 and the temp gauge has never moved above 150 indicated since I got it and the previous owner said it always did that too.
2) someone said that GM and Dexcool acknowledge a problem in the S/T series trucks. Any thoughts on this?
I don't have a CEL light, but that might be burnt out for all I know.
From my symptoms (not constantly a high idle nor dieing by any means), I don't think it is a vacuum problem. However, if anyone has a vacuum line diagram or can tell me where they all are, I could investigate it more.
Alright, that's the best that I can explain it right now.
Any thoughts? Thank you!
I'll try to explain what it is doing now.
When I push in the clutch and let off the gas, it surges up about 200rpm almost every time. It always idles back down once I come to a stop, but can take 2 - 3 seconds to start idling down. When I take my foot off the gas with the clutch still engaged (or out), it doesn't always start slowing itself down. When I push the clutch in, sometimes it will hang between 1700 and 2000 rpm. It can still pull itself down the road at 30mph in 3rd and actually pick up speed (since 28-30mph = 1800-2000rpm). If I keep the clutch out until the engine gets down to around 1000, it will stay there and not rev back up
Tonight when I got home, I experimented a little bit with the IAC, TPS, and MAP. With either the TPS or MAP unplugged, the it would idle down, but then it would hunt between 600 and 900 rpm. From this observation, I believe the MAP is still just fine. And with the IAC unplugged, it revs uncontrollably like there is a huge air leak (gee, I wonder why!).
I've read on other forums regarding the 4.3L and the 5.0/5.7L:
1) some guys try replacing the coolant temperature sensor. I might try this next as it is only $14 and the temp gauge has never moved above 150 indicated since I got it and the previous owner said it always did that too.
2) someone said that GM and Dexcool acknowledge a problem in the S/T series trucks. Any thoughts on this?
3) could low coolant cause this too?
I don't have a CEL light, but that might be burnt out for all I know.
From my symptoms (not constantly a high idle nor dieing by any means), I don't think it is a vacuum problem. However, if anyone has a vacuum line diagram or can tell me where they all are, I could investigate it more.
Alright, that's the best that I can explain it right now.
Any thoughts? Thank you!
I've actually had good luck with AZ reading codes. For the extra 5mi drive, I might as well do it out of piece of mind.
