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misses when hot


wily's Avatar
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03-28-03, 05:47 PM   #1  
wily
misses when hot

I have a 98 ford winstar with a 3.8 eng . runs great most of the time but when you warm it up to normal operating temp and shut it down for 10 to 15 minutes and restart it it will run rough and some times die give it a little throttel it will smooth out and run fine . it is not showing any codes I have replaced plugs and wires did not help . it recently had egr back pressure sensor replaced .i checked egr valve it appers to be working ok .

 
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03-28-03, 06:29 PM   #2  
could be alot of things does the check engine light ever come on. might have codes checked to see if any codes are stored in the computer, check your coolant level to make sure its not low if it is you need to find out where its going.
should also check fuel pressure to see if an injector may be leaking down causing one cylinder to be flooded upon restart.

 
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03-28-03, 08:27 PM   #3  
JSStarkey1
My brother has the 99 & had the same problem. There is a vacume line on the front of the engine (Front of compartment meaning around right valve cover), about center that kept coming loose & causing it to run rough, Skip, stall, miss, etc.. had to put a clamp on it to keep it in place

 
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03-29-03, 09:50 AM   #4  
Joe_F
I agree with both posters.

 
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03-29-03, 12:46 PM   #5  
wily
coolant level ok engine light not coming on have checked for codes no codes showing all vacume lines ok have not ckecked fuel pressure yet but will as soon as i find a gauge but would think if injector was leaking dowm it would do the same when restarting cold but it only happens when hot.

 
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04-02-03, 05:33 PM   #6  
wily
fuel pressure ok in specs of haynes can hear a whistle but can not find where it is comming from .

 
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04-02-03, 05:40 PM   #7  
did you notice if fuel pressure bled off quickly after shutting vehicle off, should maintain pressure after vehicle is shut off for 10 minutes if it doesnt its going somewhere a bad check valve in the pump will also cause pressure to bleed off, or a leaking injector.

 
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04-03-03, 05:44 AM   #8  
Joe_F
I agree with BeJay. How did you check the fuel pressure?

 
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04-03-03, 04:33 PM   #9  
wily
with fuel pressure gauge at idle vacume to pressure regulator attached and dettached and engine off after five minutes all ranges in haynes manual specs40 with vacume 45 without vacume after five minutes around 38

 
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04-03-03, 09:16 PM   #10  
when the problem occurs does it seem to be idling at a very low speed? sometimes the iac valve will stick on fords after a hot restart which could cause it to die or run a little rough due to it not idling at the correct speed.

 
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04-04-03, 03:19 AM   #11  
wily
idle dose seem to run a little lower when this happens and will pick up when it smooths out and it has a whistle when you give it a little gas this only happens when hot and does not whistle when hot unless it has been missing out .

 
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04-04-03, 05:29 AM   #12  
Joe_F
Have you cleaned the throttle body and IAC?

 
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04-04-03, 05:18 PM   #13  
wily
no i have not cleand throttle body or iac did check manual for testing procedure and possibale cleaning of iac it says it can be cleand with a soft rag . I looked the throttle body over inside did not look bad have read that throttle body on most late models should not be cleaned due to a coating inside them and on the throttle plate dose'nt look coated to me but haynes manual says it is and should not be cleaned.

 
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04-05-03, 09:10 AM   #14  
Joe_F
Only the Ford approved cleaner should be used as damage to the throttle body can occur with anything else.

 
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04-05-03, 05:03 PM   #15  
wily
should iac be tested plugged in or un plugged manual not verry detailed about that also noticed it wont act up when it is cold outside.

 
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