bigalpha
Moderator
- Location
- Tucson, AZ
I know, millions of threads about this. I searched and read but still unsure of my next move.
Specs:
- 88 MJ
- AW4
- I6
- 160,xxx miles
Symptoms:
- Truck idles high in 'D', but the idle is steady.
- I don't have tach, so unsure of RPMs.
- When shift from 'D' into 'P' or 'N', the idle will shoot up.
- Sometimes, the idle will surge. Sometimes it is not so bad.
- I have a weird blinker issue, but not sure if related.
Troubleshooting:
- No discernible vacuum leaks.
- Replaced the IACV with new but it made the problem worse.
- Original TPS tested out good but I replaced with new and adjusted.
- Fixed the serious blow by issue.
- Grounds test out .. tested via hot on batt to ground.
- Oil Pressure steady.
- When shift from 'P' to 'D', the truck engages gear and leaps forward. Same when shifting to 'R'.
- Short lag when trans downshifts. Engine will very briefly rev up before downshifting.
- Truck will accelerate on it's own and upshift through gears, maintaining about 45 mph.
Questions:
1. I think the PO adjusted the idle screw on the TB. If so, this can account for the high idle in 'D'. How do you get that back to proper setting?
2. If I unplug the IACV, should the idle speed change? Same with TPS?
3. If IACV and TPS test out properly, but the TB is really dirty from blow by, can that affect idle?
Specs:
- 88 MJ
- AW4
- I6
- 160,xxx miles
Symptoms:
- Truck idles high in 'D', but the idle is steady.
- I don't have tach, so unsure of RPMs.
- When shift from 'D' into 'P' or 'N', the idle will shoot up.
- Sometimes, the idle will surge. Sometimes it is not so bad.
- I have a weird blinker issue, but not sure if related.
Troubleshooting:
- No discernible vacuum leaks.
- Replaced the IACV with new but it made the problem worse.
- Original TPS tested out good but I replaced with new and adjusted.
- Fixed the serious blow by issue.
- Grounds test out .. tested via hot on batt to ground.
- Oil Pressure steady.
- When shift from 'P' to 'D', the truck engages gear and leaps forward. Same when shifting to 'R'.
- Short lag when trans downshifts. Engine will very briefly rev up before downshifting.
- Truck will accelerate on it's own and upshift through gears, maintaining about 45 mph.
Questions:
1. I think the PO adjusted the idle screw on the TB. If so, this can account for the high idle in 'D'. How do you get that back to proper setting?
2. If I unplug the IACV, should the idle speed change? Same with TPS?
3. If IACV and TPS test out properly, but the TB is really dirty from blow by, can that affect idle?