Questions & Answers for: Mercury Grand Marquis what fuel octane

octane, oil change every 2500, car has 55K on it now, K/N air filter. I bought some MAF cleaner and cleaned the MAF, but that didn't appear to help much. Now, last night on my way home, the hesitation

...octane with fuel injector cleaner. You will just have to drain the tank and refill with unleaded again. Then you may have to purge all of the fuel lines too. If you tried running it with the diesel ...

i run 92 octane in my 98 grang marq. , i put 87 in my 98 and it wont start just stalls out. time to change fuel filter

...octane fuel to the fuel tank. If the oxygen sensor is at fault this will have an effect on the injection times and this upset the fuel economy. Bremove the O2 sensor and check it visually. If it is ...

fuel filter & PCV valve. Checked EGR valve (SAT), use only >90 octane gas, & dumped a bottle of Seafoam in one tankful. Waddayathink? did you give it a tuneup? and if not...may try that

...octane fuel. Using 89 octane fuel alleviates the problem. The spark knock occurs under moderate load but does not occur under full acceleration. In winter months I do not notice the problem even when ...

...replaced the pressure regulator. I do not have access to testing equip. for the fuel pump. Should this be my next attempt at fixing this problem? Try some 92 octane gas first and see if that

...Check Engine or Service Engine light come? If so, was the On Board Diagnostics system checked for a codes? Usually a knocking sound during acceleration indicates a improper fuel mixture or low