Need additional HELP PLEASE !!!!!!! (UPDATE)
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Need additional HELP PLEASE !!!!!!! (UPDATE)
(UPDATE) Took it to a shop to scan, they came up with 301, bad #1 coil. I replaced it and it runs fine.
I wonder why AutoZone read code 300 ?
I had a prior post "How to change fuel injectors"
My truck 1999 F-350 4x4 Crewcab has a rough idle. It has a new longblock with 20000 miles and new coils 5000 miles. I just cleaned the MAF with a ziplock baggy and 70% alcohol, ohm tested all injectors (approx 15-15.1) range, pluged battery and check hoses for vacuum leaks. I then restarted the truck and I still have the same rough idle.
It gets smoother under high idle but when it levels off you can feel the loss of power especially going up hills
What next!!!!!
I wonder why AutoZone read code 300 ?
I had a prior post "How to change fuel injectors"
My truck 1999 F-350 4x4 Crewcab has a rough idle. It has a new longblock with 20000 miles and new coils 5000 miles. I just cleaned the MAF with a ziplock baggy and 70% alcohol, ohm tested all injectors (approx 15-15.1) range, pluged battery and check hoses for vacuum leaks. I then restarted the truck and I still have the same rough idle.
It gets smoother under high idle but when it levels off you can feel the loss of power especially going up hills
What next!!!!!
Last edited by Johnny Be Cool; Sep 10, 2010 at 08:03 AM. Reason: Found Problem
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Just a shot in the dark . . .
Have you tried unplugging the coils one at a time until you find one that does not change how it runs? At least you would know which cylinder(s) to focus on. If that doesn't resolve anything, maybe check the fuel pressure. I can't imagine it being fuel pressure, being that you say it runs okay at a high idle, but I've seen stranger things . . .
Oh, and does your truck have EGR? If it is, then it might be the EGR valve stuck open to some degree.
Have you tried unplugging the coils one at a time until you find one that does not change how it runs? At least you would know which cylinder(s) to focus on. If that doesn't resolve anything, maybe check the fuel pressure. I can't imagine it being fuel pressure, being that you say it runs okay at a high idle, but I've seen stranger things . . .
Oh, and does your truck have EGR? If it is, then it might be the EGR valve stuck open to some degree.
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After your message, I went out and unpluged the coils except for the last one on the pass side, couldn't reach it. There was only a slight difference in idle when I unpluged any of the coils. I disconnected the battery to see if I can clear any codes, I then drove to AutoZone. I have NO check engine light, they ran a test and no codes came up.
The truck has a very slight off idle feel to it. It rev's up under load but you can feel the vibration even in the steering wheel. It's not a suspension problem, it's obvious a motor problem. I can even feel the vibration (very slight) stopped at idel. When I kick it down it revs up pretty good.
I don't know what to do. I'd hate to bring to a mechanic and be charged an arm and a leg.
Any ideal on what to do next.
The truck has a very slight off idle feel to it. It rev's up under load but you can feel the vibration even in the steering wheel. It's not a suspension problem, it's obvious a motor problem. I can even feel the vibration (very slight) stopped at idel. When I kick it down it revs up pretty good.
I don't know what to do. I'd hate to bring to a mechanic and be charged an arm and a leg.
Any ideal on what to do next.
Laughing Gas
Joined: Jan 2004
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From: Denver, CO
The vehicle has to misfire a ton before you get a CEL. The number 5 COP boot on mine is cracked and causing a miss, but the screw head is rounded off and I can't remove it. I get a CEL every couple of months and it goes out on its own. My misfire is present at idle and light load up to about 2000rpm, but doesn't miss all the time under those conditions.
How did you check for vacuum leaks? There was a very common vacuum leak in a 90* fitting to the throttle body, mine was fixed under a TSB.
Good luck getting it sorted out.
How did you check for vacuum leaks? There was a very common vacuum leak in a 90* fitting to the throttle body, mine was fixed under a TSB.
Good luck getting it sorted out.
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From: Lubbock, Texas
Could be your IAC Idle air control valve. It's located on the back side of the throttle body...PITA to pull off. Only two bolts but difficult to get to. Once you get it off look inside and see if it has a bunch of gunk inside. If yes, you can try cleaning it or replacing it. I've cleaned mine without a problem but you'll need to decide. Not sure this is your problem but is a logical thing to check if your having rough idle.
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I just visually check the hoses. I really don't want to bring this into the shop. It's kinda wierd on how it happened. Was pulling a boat trailer on the Hwy the other day, it was very hot, mid-noon 99 degrees. I've been driving for 2 hours when all of a sudden this happened.
I also put a strong fuel cleaner in a 1/2 a tank. I'll drive it a few more mile and see if it pulls up a code.
Don't know what else to do.
Any suggestions!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I also put a strong fuel cleaner in a 1/2 a tank. I'll drive it a few more mile and see if it pulls up a code.
Don't know what else to do.
Any suggestions!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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I believe I replaced that a few thousand miles ago. If it's the right one your discribing. It's on the drivers side, mounted close to the TB, it has 2 small hoses attached to it one bigger than the other.
I forgot to add that I've also replaced the fuel pump 3000 miles ago.
Could it be mechanical. I hope not.
I recall when the coil went bad, it was an obvious miss, but this problem has a softer miss but feels somewhat like a coil went bad.
I forgot to add that I've also replaced the fuel pump 3000 miles ago.
Could it be mechanical. I hope not.
I recall when the coil went bad, it was an obvious miss, but this problem has a softer miss but feels somewhat like a coil went bad.
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From: Lubbock, Texas
Well...I'm running out of things to check. Question, is this a new/used motor that was just installed? Did it run good before and then all of the sudden begin to idle rough? I resently installed a new/used engine. After the first start-up I found the #5 COP plug got disconnected when we plugged in the O2 sensor. You need to get back to the #5 COP. If that's not it...you might consider the dealer to run diagnostics.
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Who installed the longblock?
Man, when I think "rough idle" and "low power up hills" together and all the other stuff has been checked...bad head gasket comes immediately to mind. Might wanna do a leakdown test on your engine.
Man, when I think "rough idle" and "low power up hills" together and all the other stuff has been checked...bad head gasket comes immediately to mind. Might wanna do a leakdown test on your engine.
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Thanks for getting to me.
I'm gonna run it for a while and see if any codes come up. If it was an EGR, you would think a code would of came up by now.
When I 1st took it to ASutozone, they said it had a 300 random code.
It could be Fuel injector, coil etc........
I'm gonna run it for a while and see if any codes come up. If it was an EGR, you would think a code would of came up by now.
When I 1st took it to ASutozone, they said it had a 300 random code.
It could be Fuel injector, coil etc........
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I'd start first by checking fuel pressure at the fuel rail, at regular idle it should be 28-30, with the vacuum hose to the fuel pressure regulator disconnected it should be 38-40, and under heavy load, it should be 38-40.
Never heard of the bag and alcohol trick with the MAF, usually brake cleaner works better, but that wouldn't happen all of a sudden like someone threw a switch.
Check the elbow where the PCV plumbing connects to the throttle body - that's a known problem.
Again, if it threw a "random misfire" code, it's not a single coil or injector.
Never heard of the bag and alcohol trick with the MAF, usually brake cleaner works better, but that wouldn't happen all of a sudden like someone threw a switch.
Check the elbow where the PCV plumbing connects to the throttle body - that's a known problem.
Again, if it threw a "random misfire" code, it's not a single coil or injector.
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Drove the truck for the day. At idel it has a liitle shake. You drive about 2000 rpm's or cruise at 60 mph around 2000 rpm's it is fine. Once you start to go up a hill and the rpm's drop to 1500 or need to give it a little gas it shakes. It appears anything above 2000 rpm's it rides smooth.