Has anyone actually figured out the rough idle?

[ZMan]

My 92 3.0l basically just sounds like its got a cam in it all the time! When its first started up in the morning it doesn't really like to stay running, ESPECIALLY if its below 50 degrees outside. It'll also surge from 1500rpm to 600rpm when I come to the stop sign a couple miles from my house. Once its warm it'll stay running and won't surge, but it still has that lumpy idle.

So far I've put in motorcraft plugs (it got a cap and rotor within the last 40k), a new coolant temperature sensor, swapped the MAF with a smooth idling truck, cleaned all the intake sensors I could find, but it still does the same thing.

Really other than the idle the truck runs like a champ and hasn't thrown any check engine lights *knock on wood*..Its been doing it since my friend bought it with 94k miles, its got 142k now.

 

[Wicked_Sludge]

id check out your TPS and IAT sensors.

there are two coolant temperature sensors, you replaced the one for the computer, right?

 

[cargs]

what about your coil? i had a problem with hard starting in the morning it was the coil.

 

[ZMan]

id check out your TPS and IAT sensors.

there are two coolant temperature sensors, you replaced the one for the computer, right?

ahh forgot about the TPS, that was the FIRST thing I replaced. I replaced the coolant temp sensor on the top of the engine near the thermostat..wheres the other one?

what about your coil? i had a problem with hard starting in the morning it was the coil.

I can try that.

 

[Jspafford]

When you say rough, do you mean like sitting at lights it stumbles and it makes ya look to make sure it didn't shut off.

I noticed that on Heather's Ranger. Weird

 

[ZMan]

When you say rough, do you mean like sitting at lights it stumbles and it makes ya look to make sure it didn't shut off.

I noticed that on Heather's Ranger. Weird

nah its not quite that bad. Just real lumpy. My old aerostar WOULD stall if you didn't hold the throttle open a little, that was fun.

 

[Southern3.0]

Thats almost exactly how my old '91 would run, even after I swapped all the sensors, coil and a few other parts except for the Maf and 02's off a perfectly good running Taurus (Trans was bad). Never figured out what was up w/ it, but other then the idle the truck ran great so I never really worried about it

 

[therangerofdanger]

if you have access to a scan tool look at EGR flow even though that should set the MIL but it is OBDI if that were the prob. to much EGR flow gives you exuast flow at idle when the EGR should only allow flow at crusing. doing this will give you a rough idle. if it is at 10% that should cause an idle problem anything higher should stall the engine. also check you IAC (idle air control) that is a good possibly to your idle problem. if there is to much "grime" could clog up the pintle and seat in your IAC valve. check those if you haven't figured it out. they are alittle cheaper than a coil pack and other things.

 

[ZMan]

if you have access to a scan tool look at EGR flow even though that should set the MIL but it is OBDI if that were the prob. to much EGR flow gives you exuast flow at idle when the EGR should only allow flow at crusing. doing this will give you a rough idle. if it is at 10% that should cause an idle problem anything higher should stall the engine. also check you IAC (idle air control) that is a good possibly to your idle problem. if there is to much "grime" could clog up the pintle and seat in your IAC valve. check those if you haven't figured it out. they are alittle cheaper than a coil pack and other things.

EGR delete option Old 3.0s are also distributor engines. I'll try cleaning my IAC, thats about the only thing I haven't tried. If its not that I give up because I'm not buying a IAC, too much $$.

 

[joemohio]

Same problem here. 93 3.0 4x4 5 spd. on cold start ups it will run so rough that I will turn it off because it makes no sense fighting it . If I turn it off and fire it right back up its fine. I Have still have the lumpy idle when it warms up though. Another good one is if I stall it in the morning, (half a sleep clutch foot) Then try to start it up I have to hold the gas to the floor or it wont start. Acts like its flooded.
Now I dont know how true this is but I believe there is a ford update (recalibration)for the engine computer that takes care of this issue. I have been meaning to take it in to have that done but havent made it there.
Any one heard of this recalibration for this issue?

 

[Wicked_Sludge]

you cannot recalibrate eec-iv. ive driven several rangers (mine included) that have had the cold startup after stalling issue. holding the gas pedal to the floor while cranking signals the computer to cut injector pulse to zero....so if this helps for you, then the truck is definately running rich.

 

[ReD-rAnGeR]

what about fuel injectors?
my 98 has a rough idle after new plugs and wires

 

[creepinjeepster]

Mine was doing this. Ended up changing the FPR and got a IAC off a newer model 3.0 from the JY. (Had to cut the harness for it too and swap). Been idling fine ever since.

 

[ForOffRoadDriving]

mine has the same problem with the cold stall if i get lazy when taking off. i have to pedal down to get it started. something simple i havent heard anyone mention is the hole in the throttle plate, make sure its clean and un restricted because thats where the air goes into the intake at idle.

 

[ReD-rAnGeR]

i had the same problem. i replaced plugs, wires, and the iac today. idles better but it still stumbles at regular idle after it is warmed up