Mechanics

DOES INSIUFFICIENT FUEL SUPPLY CAUSE ENGINE MISFIRE?

1996 Ford Windstar • 223,000 miles

I have recently been having problems with my Ford Windstar 1996. The engine seemed to misfire regularly on the way back from Vancouver the other day. When climbing or decending down steep hills, the engine seemed to stutter, skip to higher revs and then drop back down to normal. Fuel level was low. Although the engine warning light was already on, diagnostics said Cylinder 4 and 5 misfire.

The car this morning ran fine, no misfires, no transmission issues, like the car was like new. During a service this morning, and having previously diagnosed transmission problems, I changed the trans fluid and found no metalic deposits of any kind. Trans fluid was also good.

I changed the spark plugs and cleaned the throttle sensors. When leaving the workshop the car again misfired and the previously clear CEL came back on, and put the car in Limp Mode.

Has anyone heard of this before. Ive had no issue with the car until I get lazy and run the fuel levels down. Im not convinced that its a transmission sensor issue as its intermittent, with the car always starting from cold very well, and then starting to misbehave later in the journey.

Any ideas?
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Wallsey
April 29, 2012.



Did you change the wires and coil too? That would be for the missfire.

As far as the trans in limp mode, that is an internal issue, not a sensor.

Roy

ASEMaster6371
Apr 30, 2012.
Lack of fuel pressure and or volum will give you misfires but being low on fuel in the tank will not. Have the fuel pressure tested

Djcl
Apr 30, 2012.
Thanks for the replies. Ive just given it another test run. The car started first time and drove for 10 mins without issue. The engine then stumbled (unsure of why), and then limited itself to 2nd gear. I restarted the engine and proceeded 10 furthur minutes without issue, the car shifted gears as normal. The car then stumbled again (when coasting at a steady temperature, the car stuttered, revs increased temporarily) and then limited itself to 2nd gear once again.

In terms of isolating the problem im at a loss. The inconsistency is what is driving me mad. Whilst driving in limp mode (or what im assuming only being in 2nd gear is) there is consistent performance, albeit at a higher rev and lower speed.

Would the car go into limp mode to protect itself from any furthur misfires? Would transmission issues be constant from engine start up?

Thnaks for your help guys
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Tiny
Wallsey
Apr 30, 2012.
No, it would not. Limp mode is a mode to allow you to keep moving to get off the highway.

The missfire issue has not gone away and will get worse.

You need a shop to at least check it for you.

Roy


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