2000 dohc rough idle
I am working on a 2000 Taurus with the DOHC 3.8 that is missing very badly and stalling at idle. The car originally had a code for insuffient EGR flow, and I replaced the EGR solenoid and it did't seem to fix the problem, as the code came back after clearing it. The idle quality has recently gotten very bad, and in addition to the original EGR code, I now have codes for "system too lean" on bank 1 and on bank 2. I replaced the throttle position sensor, idle contol module, pcv valve, EGR valve, both O2's before the cats, spark plugs, fuel filter and air filter. This made no difference whatsoever, and all the above codes came back and now it also had codes for "manufacturer fuel metering malfunction" and a code for the heated O2 sensor on bank 2.
The car runs fine above 1200 rpm, and does not miss at all and accelarates fine. It misses very badly at idle and will even stall if left sitting for more than a few minutes. Could this be related to the cats ? Any ideas on what else to check ? I am completely out of ideas at this point and would like to avoid taking it to a shop. The car currently has 90K miles.
Thank you in advance for any help or ideas.
sounds like you have covered everything.could be cloged cats,do the drill test,drill a 1/8 hole in the down pipes BEFOR cats ,see how it runs,put screws back in holes drilled or wield them,if it runs right the cats are the problem. MONRO will also do this test for free,at least here in va.
My girlfriends car (2000 Ford Taurus DOHC) had a similar sounding issue. It ended up being the lower plenum intake manifold gaskets. An easy way to check to see if this is the problem is to spray brake cleaner along the interface between the lower plenum and cylinder head (would also work by spraying brake cleaner between upper and lower plenum if the leak is in that region). The idle should pick up momentarily right after spraying the brake cleaner. The idle will go rough again after a second or two. However, if it reacts to this then odds are it's the intake gaskets. You can get a full set of intake gaskets for around $15 bucks at most auto parts stores. The repair isn't too complicated and can be performed by a novice/average mechanic in around an hour and a half if great care is taken. Ensure to not get ANYTHING in the intake ports once the intake manifold is off. Hope this helps someone.
Pull the EGR valve itself and see if there isn't something on the seat causing a leak. The valve itself might also be hanging open even with the new solenoid. Either will allow excess stuff into the intake that isn't supposed to be there and cause idle problems as you describe.
Have a taurus changed plugs and wires ran good for 2 minutes then ran like crap WELL the new plugs where( brand new crap autolite) changed with bosch OH happy day.
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