'92 302 Idle Problem
Senior User
Joined: Jan 2001
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'92 302 Idle Problem
I just bought a '92 F-150 SuperCab 4WD (302/auto) with only 35,000
miles. Yes, you read right, only 35K miles! Upon start up, the idle shoots to over 1000 RPM and stays there for more than 2 minutes and then calms down to a normal range. It seems too long for such a high idle. The engine also idles slightly rough. I've changed out plugs, wires, cap/rotor and air filter with no change. I heard that some 302s have a slightly different firing order. The old plug wires didn't look like they had been moved since it left the factory. Would the engine still run(but idle rough)if the wrong firing order had been used? Any help would be appreciated.
'92 F-150 4WD
'94 Explorer 4WD
'95 E-350 Chassis Motorhome
'92 Jeep Wrangler (oops! 3 Fords out of 4 aint bad!)
miles. Yes, you read right, only 35K miles! Upon start up, the idle shoots to over 1000 RPM and stays there for more than 2 minutes and then calms down to a normal range. It seems too long for such a high idle. The engine also idles slightly rough. I've changed out plugs, wires, cap/rotor and air filter with no change. I heard that some 302s have a slightly different firing order. The old plug wires didn't look like they had been moved since it left the factory. Would the engine still run(but idle rough)if the wrong firing order had been used? Any help would be appreciated.
'92 F-150 4WD
'94 Explorer 4WD
'95 E-350 Chassis Motorhome
'92 Jeep Wrangler (oops! 3 Fords out of 4 aint bad!)
New User
Joined: Feb 2002
Posts: 18
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From: Barnesville
'92 302 Idle Problem
I recently purchased a '92 with a 302 also. It does same thing upon starting. The Check Engine light comes on and I had the codes scanned before purchase. The codes (forgot numbers) report possible 2 bad sensors. I'm having the most likely one replaced next week to see if that clears the check engine light problem and will then address the high idle problem. I've found that if I punch the gas a little while its idling high it drops down to a decent "startup idle" (just a little higher than normal). It might be cable related (sticking, etc.). Good luck with yours!
Thanks,
BL...
Thanks,
BL...
Posting Guru
Joined: Jan 2001
Posts: 1,124
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From: Rural Florida Panhandle
'92 302 Idle Problem
I had a 92 F150 5.0 5 speed which had the high idle at startup and changing idle speed thereafter problem. I replaced, cleaned, checked everything..including a new MAP sensor (about $60). No change.
At the suggestion of my wife, I started pretending I had a carb with automatic choke, and after every cold start, would goose the pedal to set the idle. For 2 years, until I sold the truck, this worked. If I ever forgot to "set the choke", the idle would suddenly jump up at a traffic light or intersection, of when stopping. The only way to fix it was to shut off the engine, wait a few seconds, then immediately goose the throttle as soon as it was restarted.
Goosing the throttle after the problem starts did not work, without shutting down the engine and restarting. I suppose some delay mechanism in the ECM was defective. Anyway, whatever works....
Winford
At the suggestion of my wife, I started pretending I had a carb with automatic choke, and after every cold start, would goose the pedal to set the idle. For 2 years, until I sold the truck, this worked. If I ever forgot to "set the choke", the idle would suddenly jump up at a traffic light or intersection, of when stopping. The only way to fix it was to shut off the engine, wait a few seconds, then immediately goose the throttle as soon as it was restarted.
Goosing the throttle after the problem starts did not work, without shutting down the engine and restarting. I suppose some delay mechanism in the ECM was defective. Anyway, whatever works....
Winford
Senior User
Joined: Feb 2002
Posts: 402
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'92 302 Idle Problem
It's normal for the idle to be high for a few minutes on a cold start.This is a fuel injected choke if you will.If the idle is unstable after it comes down,check out the idle air control valve and the throttle body.It's not uncommon for the IAC ports to get fouled.Also check the throttle position sensor operation.
Billy
Billy
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