Ford Repair: 1987 F-150\ 220000 miles,orig. eng., air control valves, air control valve
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Question -
my truck has an intermitant rough running condition under light load conditions.this problem dosent occur durring acceleration.at times the engine preforms perfectly.when this condition does occur its only at idle or under light eng. loads.i've changed plugs,wires,cap & button w no help.also this condition seems to change temparorly when i disconnect one of the thermactor air control valves mounted next to the coil.how can i isolate this problem.please help,thanks.
Answer -
GARY
it could be your egr.its hard to say without hooking the truck up to a scan tool. if the thermactor air control changes the condition it sounds like emissions.block off the air control and idle air control and see if condition changes.also be sure to check the egr like i said.hope this helps.
ken Thanks Ken for the response.Since I wrote eairler I've realized the thermactor air control valve does not affect the way it runs.Is there a good resourse for info on "how to" diagnose & or isolate the problem?I'm not sure how to block off the idle air or air control valves or what I need to ck the egr sys.Would a scan tool be worth the investment or should I take the truck to the shop?I would like to be able to learn more about the emissions system if possible.Thanks again.Gary
AnswerGary,
Take your truck to the shop and ask them to place in the scan tool for you and let them diagnose the erg sys. as a scan tool starts at 3 grand and up.
As for learning more on emissions systems and how to diagnose and/or isolate problems, go to your local auto parts store, such as Auto Zone, Napa or Advanced Auto and pick your self up a Chilton's manual on emissions or go to their web site to order one: www.chiltonsonline.com
Hope that this helps and good luck. Please let me know if you need more help. I also apologize for the lengthy response time as I was experiencing technical difficulties with my ISP.
Ken
