QuestionQUESTION:
"hi there, we just recently got a ford f250 super duty 2001 make from a friend. he's never had a problem and we didnt have one until last night. we were driving , when excelrating at about 45 - 60 mph it started to shake and vibrate really bad. seemed if we gave it more gas and pushed it to go it got up to 62 mph and was fine. also noticed a change in the idling of it at the same time when we stopped to check the truck. it was idling very shaky ( did not feel like it was gonna shut off ) just shaky and very vibating?? this morning we noticed a noise under the hood, when looked at the pc value it was like a whistling sound or humm. it was not doing that th enight before. im listing all of this because i didn not know if it all could be related somehow? thank you for your help."
ANSWER: Johnny,
I need to know if this is a diesel or a gas engine? I need to know this before I can make a good answer for you.
Matt
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QUESTION: gas engine. thanks. also we washed the truck and under the hood with a de greaser, because it had never been done before and needed it badly. just in case that would help. thanks.
ANSWER: Johnny,
Without hearing the sound it is making it is hard to pinpoint the issue but, it sounds to me as if you have a vacuum leak. A big one! This will lean out the engine's air/ fuel mixture and cause bad combustion. Lots of times it makes the engine idle higher but rougher. The whistling sound could be from a vacuum hose or fitting broken or loose. Also check the PCV valve and hose if equipped. While driving from 45 at cruise speeds vacuum values are high but when you accelerate to 62 and press the gas the vacuum drops due to air entering the intake reducing vacuum. That would explain the reduction in the shutter
Option 2- there may be a sensor bad somewhere. You can take it to the dealer and have the computer scanned and they can check the operation of all of the sensors and compare it to the proper parameters to see if they are operating correctly.
I hope some of this gives you and answer to your problem, I will do some homework and see what else I can find and will shoot it your way as I find out
Matt
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QUESTION: at this point , any suggestions helps. since we have talked to you. we had it at a shop to do a disgnostic check. they found nothing, besides they think it was a secondary or random missfire they said, they said they did a compression test on all of the coils, checked all the coils and spark plugs and there didnt seem to be anything wrong.also the reason why imentioned thatwe washed the truck , is because someone also suggested that maybe we got something wet electrical for it to be doing that? but what electical wire ( if got wet) would make the truck do something like that? newly, someone also suggested fuel injectors , or perhaps adding a octane booster to the fuel? ever heard of that? just throwing some things at you ... your help is greatly appreciated!
AnswerJohnny,
I'm still investigating the issue but there may be truth to the suspect of the fuel injectors. They need a certain pulse width to operate proerly( Time they spray fuel) if there is a sensor ie: crankshaft position sensor or camshaft position sensor going bad they don't know when or how long to spray fuel, causing a possible misfire. The plugs have weatherpacks in them to keep moisture out and if they are gone or bad the moisture could have effected their operation. Check a service manual (HAYNES or CHILTONS) to find these sensors and unplug the harness and check for moisture and corrosion on the connections. this may be your problem
Matt
