idle speed issue

1995 PONTIAC TRANSPORT
225,000 MILES • 3.8L • 6 CYL • 2WD • AUTOMATIC
Avatar
FIXITMR
  • ✓CERTIFIED EXPERT
  • 9,990 POSTS
picked up a 95 transport 3800 plastic upper intake that has been sitting for some time. it runs fine but the idle speed increases when warmed up to temp. it goes from 700 up to 2000. turning off and restarting brings it back down but it then rises again within 5 min or less. check engine light is on but i have not got codes.
Feb 9, 2016 at 12:49 AM
Advertisement
Avatar
JOHNNYT73
  • CERTIFIED EXPERT
  • 924 POSTS
Take it to the parts store to get codes. You can start by getting a can of throttle body cleaner and cleaning the throttle body on both sides. Removing it to clean it would be best.
Feb 9, 2016 at 5:32 AM
Avatar
FIXITMR
  • CERTIFIED EXPERT
  • 9,990 POSTS
Anything special about getting codes? I got pre 96 code reader which just jumper read codes from engine light?
Feb 9, 2016 at 10:35 AM
Advertisement
Avatar
JOHNNYT73
  • CERTIFIED EXPERT
  • 924 POSTS
Yes, count the flashes
Feb 9, 2016 at 10:37 AM
Avatar
FIXITMR
  • CERTIFIED EXPERT
  • 9,990 POSTS
no luck yet my reader seems to have different pins then the under dash connector! but i did notice 1 thing testing the idle again and that it rises when i put it in gear after starting to warm up. it also rises and falls 300rpm sometimes just sitting in park. maybe it just needs some driving the van was sitting a long time 6 mths or so and it had sat for how long before the previous owner bought it.
Feb 10, 2016 at 4:33 PM
Avatar
FIXITMR
  • CERTIFIED EXPERT
  • 9,990 POSTS
ok found out from net this yr has weird system for terminal access cant read flashes scan tool only so i guess i'll try autostore.....
Feb 11, 2016 at 12:16 AM
Avatar
FIXITMR
  • CERTIFIED EXPERT
  • 9,990 POSTS
aint got to store yet dont trust it yet. but as i mentioned before, idle rises after initial fast idle start and then slowdown and it generally happens when i put it in/out of gear several times. returns to normal if i shut off and restart. so as a whim, i disconected the IAC plug when it was warmed up/idle was correct. it did NOT raise after that........gonna see if will run cold tomorrow with disconnect.
Feb 11, 2016 at 4:49 PM
Avatar
JOHNNYT73
  • CERTIFIED EXPERT
  • 924 POSTS
Ok, sounds good
Feb 11, 2016 at 4:50 PM
Avatar
FIXITMR
  • CERTIFIED EXPERT
  • 9,990 POSTS
took it for a ride today from cold start idle was ok after i pedaled it for 30 secs i'm gonna call that good for now i found another problem something is wrong with steering it veers on its own! he said he hit a big pothole so maybe rack is loose?
Feb 12, 2016 at 4:07 PM
Avatar
JOHNNYT73
  • CERTIFIED EXPERT
  • 924 POSTS
I don't think it's loose unless you feel a lot of play in the steering wheel. Could just need a wheel alignment done.
Feb 13, 2016 at 4:09 AM