RPM changes
#1
RPM changes
HVAC off. When moving selector through gears, it often drops to about 500 RPM and then move back up to about 600 except 1st which moves back up to about 550 RPM. Neutral has idle of about 725 RPM.
Torque converter stall speeds seem to be consistant.
Is there some sort of relearning for PCM? It acts like it is hunting.
What could be causing this?
Idle does seem like it has mild skip which was there before changing plugs and installing new Visteon COP's. I changed them out for that reason and that water got in a couple of plug wells thus displaying code. No codes now.
Torque converter stall speeds seem to be consistant.
Is there some sort of relearning for PCM? It acts like it is hunting.
What could be causing this?
Idle does seem like it has mild skip which was there before changing plugs and installing new Visteon COP's. I changed them out for that reason and that water got in a couple of plug wells thus displaying code. No codes now.
#2
That sounds normal to me, mine does that too. The idle air control valve has a small amount of lag to it. Mine has been like that since new, regardless of coil type or plug. I now have NGK Iridiums and granatelli street fighter coils. A master mechanic I know said the small skip was a lean mis. Our trucks have dual cats each side and were considered LEV's. Low Emissions Vehicles. I just took that sticker off the driver front window when
they got tinted. If the RPM's bounces more than once it could be a leak or failing IAC. Also clean the MAF with MAF cleaner.
they got tinted. If the RPM's bounces more than once it could be a leak or failing IAC. Also clean the MAF with MAF cleaner.
Last edited by 01 gt f150; 09-20-2014 at 07:46 PM.
#3
#6
What oil was used on the last oil change? With that low miles and it's age it could be sticky rings. I had that issue on another vehicle before. It sat for 2 years. I check compression and it was very low so I put 2 tablespoons of transmission fluid in each sparkplug hole and let sit for a day. The next day I turned it over with plugs out a couple of times then re-installed plugs. It smoked a bit till the tranny fluid burned off but solved the oil consumption. The tranny fluid desolved the carbon build up on the rings. I'm sure jbrew may have some additional Idea's. He is very well known for his knowledge and advice.
#7
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#8
What oil was used on the last oil change? With that low miles and it's age it could be sticky rings. I had that issue on another vehicle before. It sat for 2 years. I check compression and it was very low so I put 2 tablespoons of transmission fluid in each sparkplug hole and let sit for a day. The next day I turned it over with plugs out a couple of times then re-installed plugs. It smoked a bit till the tranny fluid burned off but solved the oil consumption. The tranny fluid desolved the carbon build up on the rings. I'm sure jbrew may have some additional Idea's. He is very well known for his knowledge and advice.
#9
Since I changed all COP & plugs symptoms are about the same. None of the plugs showed unusual signs toward buildup. I'll double check to see if any show too much toward lean side (old plugs).
#10
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If you are seeing oil consumption the PCV would be the first thing I changed.
Use a motorcraft one. I did mine at about 70,000 miles when I saw my oil consumption go up slightly and it fixed the problem. For what it cost it is a no brainer to me.
Cleaning the IAC and throttle body is also cheap. A few cans of TBC and your time.
jethat gave you some good tips there and they cost very little.
Use a motorcraft one. I did mine at about 70,000 miles when I saw my oil consumption go up slightly and it fixed the problem. For what it cost it is a no brainer to me.
Cleaning the IAC and throttle body is also cheap. A few cans of TBC and your time.
jethat gave you some good tips there and they cost very little.
#11
If you are seeing oil consumption the PCV would be the first thing I changed.
Use a motorcraft one. I did mine at about 70,000 miles when I saw my oil consumption go up slightly and it fixed the problem. For what it cost it is a no brainer to me.
Cleaning the IAC and throttle body is also cheap. A few cans of TBC and your time.
jethat gave you some good tips there and they cost very little.
Use a motorcraft one. I did mine at about 70,000 miles when I saw my oil consumption go up slightly and it fixed the problem. For what it cost it is a no brainer to me.
Cleaning the IAC and throttle body is also cheap. A few cans of TBC and your time.
jethat gave you some good tips there and they cost very little.
I had no idea Ford had gutted that engine to 16V and stuck it in trucks.
That said, I feel you might be right about IAC and throttle body cleaning. I would have ordered PCV as well as fuel filter, etc. but they had no FMC one. I had read somewhere in forum it was important to go back with a Motorcraft.
I say IAC because it is a little rough at idle but running above that seems smooth. Although the programming of the computer seems to suck as downshifts seem too soon and often upshifts are delayed. Like it was programmed only for towing and hauling, never running empty.
I have not seen one or TSB saying one came out, did they make a new program?
(It really needs one)