runs rough when warm?
Thread Starter
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Elder User
Joined: Oct 2008
Posts: 550
Likes: 1
From: Colorado
runs rough when warm?
Hey fellas, I have an 89 f150 302. About 140,xxx miles on it. Its very well taken care of. I have a weird problem when the truck warms up. It misses when in gear and at a stop almost stalling. If I hold the brake and apply a little gas you can blatantly hear the miss. But it only does this when warmed up.
I have ran codes in KOEO and KOER and both got a pass code.
I have replaced the following with OEM motorcraft:
Ignition coil
Tps
Cap
Plugs and wires
injectors
TFI module
fuel filter
Fuel pressure regulator
I ran a fuel pressure test with gauge and it was fine.
Cleaned EGR and checkrd for vacuum leaks and also replaced MAP sensor.
I'm currently at a loss and pulling my hair out. Its a consistent problem only when warmed up and at idle speed. Cruising down the highway its fine.
Subford, you have any ideas? A possible PIP? I've also done a timing check and its right at 10* btdc.
I have ran codes in KOEO and KOER and both got a pass code.
I have replaced the following with OEM motorcraft:
Ignition coil
Tps
Cap
Plugs and wires
injectors
TFI module
fuel filter
Fuel pressure regulator
I ran a fuel pressure test with gauge and it was fine.
Cleaned EGR and checkrd for vacuum leaks and also replaced MAP sensor.
I'm currently at a loss and pulling my hair out. Its a consistent problem only when warmed up and at idle speed. Cruising down the highway its fine.
Subford, you have any ideas? A possible PIP? I've also done a timing check and its right at 10* btdc.
Post Fiend
Joined: Feb 2009
Posts: 8,005
Likes: 7
From: Ottawa, Ontario
Hows the coolant level? Is it going down? Mixing in with the oil?
My 300 was doing what your describing when it blew the head gasket. What confirmed it for me, was the loosing coolant, and severe blow by with the oil fill cap removed with engine running.
My 300 was doing what your describing when it blew the head gasket. What confirmed it for me, was the loosing coolant, and severe blow by with the oil fill cap removed with engine running.
Thread Starter
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Elder User
Joined: Oct 2008
Posts: 550
Likes: 1
From: Colorado
Thanks for the reply.
No loss of coolant, the oil is still very clean for 2000miles on an oil change. And the plugs colors are perfect.
I just tried a distributor from a working truck with no issues and still had the same sputter when warm. I double checked ACT sensor and about everything there is to test resistance and everything was spot on.
Looks like I'll be taking it to a mechanic tomorrow. Im in fear its either a simple fix or I'm going to need some lube when they rape me on price.
No loss of coolant, the oil is still very clean for 2000miles on an oil change. And the plugs colors are perfect.
I just tried a distributor from a working truck with no issues and still had the same sputter when warm. I double checked ACT sensor and about everything there is to test resistance and everything was spot on.
Looks like I'll be taking it to a mechanic tomorrow. Im in fear its either a simple fix or I'm going to need some lube when they rape me on price.
Junior User
Joined: Jul 2012
Posts: 58
Likes: 0
From: Lockport
thumper- from how you describe your issue it seems we have the same issue. replaced almost everything under the hood. It doesn't act up until its warm. I did notice my truck runs better with the pcv system plugged. not sure why. sorry for highjacking your thread by the way. still kinda havin the same problem as before and there are only so many things that can get replaced. next up is a gasket kit from the block up.
Logistics Pro
Joined: Mar 2005
Posts: 4,698
Likes: 47
From: Mexico, Missouri
Ok, shoot'n from the hip. Before you take the truck to mehanic (probably already did though), pull PCM/ECM. Remove and check for bad caps, burnt traces, resistor burns.
Similar problems that ultimately lead to my disabled '92, 300...
Similar problems that ultimately lead to my disabled '92, 300...
Thread Starter
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Elder User
Joined: Oct 2008
Posts: 550
Likes: 1
From: Colorado
Yeah its already there. I have checked the ECM before and it was fine. No burn marks or rusty connections. I'm going out of state for a week so hopefuly they have it fixed when I come back.
Mountain Pass
Joined: Aug 2005
Posts: 140
Likes: 1
From: Seattle
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Cargo Master
Joined: Jun 2013
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Such a shame a high percentage of folks use these forums for information, and don't provide a final response, How many threads have I read over the year that were a waste of time. But, many have been of great value. I support a small fee, to keep the guessers, etc, off the threads. Venting.....
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