Idle Flare UP

[XfireZ51]

Got the car out of its deep winter slumber today. Temps close to 60 here in Chitown and may hit 80 this week. Car started fine and idled fine for 10-15min, then the idle flared upwards to aboput 1500rpm and dropped. Did this a couple of time without any indication. It would idle back down to 750 or so. I had a code 43 which I believe is knock sensor, but I think this is a result of the flare-up not the cause. Cleared the ECM and drove him with no further DTCs. Nearing home I did get a bit of a backfire through the exhaust and noticed that the idle was not dropping as quickly. Anyone else experience anything like this after bringing car back from deep slumber?

[Ccmano]

It's just excited to be awakend from it's winter time slumber. Kinda like morning wood...:sign10:

Just let it see the light of day and drive it, see what happens.
H
:cheers:

[QB93Z]

I suggest checking all of the connections to the Plenum. Also, you may have a problem with the MAP (Manifold Air Pressure) Sensor. Check the hose to the MAP and make sure it is not softened and collapsed.

Jim

[-=Jeff=-]

Check for Mice or remnants of.....

[XfireZ51]

I suggest checking all of the connections to the Plenum. Also, you may have a problem with the MAP (Manifold Air Pressure) Sensor. Check the hose to the MAP and make sure it is not softened and collapsed.

Jim

Jim,

I thought about that or the TPS being in one spot for so long that there may have been a bit of oxidation. With use it wore off possibly. Just bought 3 Ltrs of the Castrol GTX 10W-60 for the trans (@$10) AND 12 Qts of the Castrol 15W-40 Diesel (high zinc) for the oil change. Next up is replacing clutch pedal. Get ready for run to BG in case I go.

[GOLDCYLON]

Failed IAC or TPIS ?:hello:

[-=Jeff=-]

Maybe a loose nut behind the wheel :sign10:

[LGAFF]

Usually a bad tune, might want to get a new stock chip, check the for sale section.:sign10:

[Demps]

Stuck injectors.

[XfireZ51]

Usually a bad tune, might want to get a new stock chip, check the for sale section.:sign10:


Always good humor from Lgaff.
I disconnected the BAT, then opened ECM. I use an Ostrich so I pulled connections apart including adapter. That seemed to work as far as the flare up. Didn't experience any after that altho I did have what appears to be a sticky throttle at the end. Car going up on jacks tomorrow and fluids begin to drain. :hello:

[Paul Workman]

The backfire, knock sensor, etc makes me think "LEAN". Could be as simple as a vacuum "leak" due to torque (lack thereof) on one of the gaskets. Just for fun, go 'round the plenum and check torque on the plenum bolts. If you find a loose one, then too then I'd think about re-torquing the IH bolts too, if the problem persists. (You did plug the IH coolant holes, didn't ya?) Oh, yeah...My brake booster hose caused that one time: got soft on one end, so I replaced it and idle settled down...Just a thought.

Are you sure it isn't just your tires slipping causing the run-up in rpm? (We've noticed you have a little problem getting traction...:sign10: But, who am I to say anything, huh???)

Did I mention it intermittently running LEAN?:rolleyes::mrgreen:

P.