2004 Mercury Sable Starting Issues

HELP!!! I have a 2004 Mercury Sable that has intermitent starting issues. When the vehicle does not want to start if you pump the gas a little eventually it will start. I took it to the dealer who hooked it up to the diagnostic computer. The computer said that is was a Mass Airflow issue and Idle Control Valve. The wanted $600 to fix the problem. Being the non-mechanical type I decided to fix it myself. I saved a lot of money and replaced the parts. But the problem is… It did not fix the original starting issue… plz help.

Geez, I wish you had asked before you replaced the MAFS and IAC. Was the check engine light on? I don’t think that the IAC sets a code so I dunno what they were looking at! At least you have a spare MAFS and IAC and they don’t take too much space. At least not as much as a spare transmission.

Did they check the fuel pressure? Since it is intermittent, it will be hard to diagnose. Low fuel pressure at start-up can often be pinpointed by turning the ignition on for a couple of seconds and then turning it off. Repeat that once or twice and then engage the starter. Cycling the ignition cycles the fuel pump on and off.

Absolutely nothing to do with pumping the accelerator. You replaced the parts - is the check engine warning light on? No? You need a cptr scan. Cheap handheld digital readouts around $30 - $50 more if you want better data. Look for a latent code to determine if there is a sensor problem. If no warning light and no codes, turn the ignition to test position just before crank. Listen for the pump. Wait a second or two and start. No warning codes and no start after hesitation - likely pump but first change out the fuel filter.