Engine Performance problem
1999 Mercury Marquis V8 Automatic 4.6 miles

Good morning all,

Hopefully you can assist. I have a 1999 Mecury Grand Marquis with 130,000 miles on it it has been giving me problems on accleration and idle where it feels like its going to cut off and when i hit the gas the car feels as if its losing power and a fast blinking Check Engine light comes on then turns off.
I have changed the following.
1. Spark plugs
2. Air filter
3.Fuel Filter
4. cleaned the Throtle Body
Any ideads what it might be ?

Thank you

Have you pulled the codes? Go to Auto Zone or O'Reilly's and for free they will pull the codes. With the Check Engine light coming on we need to know what codes it is telling you. Also, does it do this just at take off and if you are sitting on a very slight hill or driveway with a slight incline, then as you give it a little gas, as you slowly start to go up the hill/driveway does it want to hesitate? Let us know.

I will go today.


What happens is when i accelrate or when its idle then only way i can explain it feels like it wants to cut off like a misfire. the check engine light doesnt stay on it flashes then turns off

Go to autozone and have them pull the codes they will be able to tell you what is stored in the computer and then you can go from there please let us know what the codes are and we can hlp you more

Hello all,


Sorry for the delay on the answer back i went to autozone on Saturday and no codes were showing i had freind who has a snap on scanner he hooked it up and nothing no codes....I had someone tell me it was the idle air control valve tried that and the car still runs the same sluggish when i turn on the a/c its worse but it doesnt matter if the car is drive or netural it still jumps and feels like it wants to cut off

check fuel pressure check for vacuum leak, cam and crank sensors and plug wires see if you are getting any stray sparks jumping from wire to somewere on engine if you replaced with autozone wires I have been having alot of probblems with there wires lately so I back getting oem wires.

Hello
In rereading the info – you never stated that you replaced the plug wires. As jnovack stated, jumping sparks can do this. PLEASE BE CAREFULL, LOTS OF MOVING PARTS! Take a spray bottle with water. Start the engine. Spray a mist (don’t soak) a mist over the plug wires to include where they connect to the plugs. If the engine sputters, the spark is jumping.
Also, PLEASE BE CAREFULL, LOTS OF MOVING PARTS AND NOW ITS DARK TOO! at night, no lights, the darker the better, crank the engine. Look at the engine really close with no lights. Sometimes you can see the spark jumping. As jnovack stated, sometimes you need the OEM wires. Also, this car calls for plug type, Motorcraft AWSF-32P. Sometimes not going with the OEM plug isn’t good either. Make sure the gap is correct. Are you sure when you put the plugs in they are at the proper torque and the ceramic insulator didn’t get cracked?
Last – not throwing a code can be aggravating. Makes it harder to figure out obviously. Keep this in the back of your mind as a thought. Could be the EGR valve, solenoid etc. I have attached a site for you to review and do this test.
Let us know…..good luck