Engine Performance problem
2000 Mercury Sable 6 cyl Front Wheel Drive Automatic 112K miles
I have a 2000 Mercury Sable with the 3.0 overhead valve motor.
I have done a number of tuneup procedures in recent weeks to keep the car in it's reliable condition. I like to keep this daily driver running forever. Up until yesterday I did the following and everything was running ok:
-Changed fuel filter (used Motorcraft Platinums)
-Cleaned K& N Air Filter
-Seafoamed treatment and changed oil after Seafoam procedure
-Flushed radiator fluid and replaced
This is where things get hazy. Yesterday I changed out the plugs and cleaned the MAF and throttle body. For the plugs I used Autolite single Platinums gapped to 0.044 (within range). I checked all connections to make sure all was well and checked the vacuum lines for leaks, everything was securely connected with no problems. Autolite single Platinums were used on this car in the past and it didn't have an issue.
After I buttoned everything up I started the car and all seemed fine. The idle at park was were it needed to be (approximately 1000-1100 rpms) but after one minute the idle started to surge as if it was about to stall. I placed the vehicle in reverse and drive and for a moment again all seemed well but it dropped again.
I took the car out for a spin and it doesn't appear to have an issue. The check engine light did not appear and everything runs great when at speed. It acted this way during the test drive and on my drive to work this morning.
I get to the office and decided to sit in the car with the motor idling just to see if the roughness would appear. Sure enough it did. So all is well when at speed but after a moment when it's back at idle the issue returns.
I intend to go over my steps later this evening. Recheck the wires and plugs, making sure there is a good connection. Last night I checked the IAC and it appeared ok and clean for the most part. I wouldn't think it would be the throttle body. After rechecking the plugs I'm going to revist the MAF, they seem to be very sensitive that the smallest movement seems to aggravate them and the engine as a result.
I didn't use a cleaner on the MAF because of testimonials I have heard about residue creating havoc on the MAF's performance so I wiped the inner housing with a lint free cloth. The check engine light has not appeared from the time I changed the plugs, the MAF and throttle body cleaning until now. Is there anything else that I am overlooking?
Monday, June 9th, 2008 AT 7:05 AM