Questions and Answers

Mercury Marquis Vacuum Lines Q. Hi, My name is John and I am a 21 year old electrical worker. I have this beautiful 1988 5.0 liter EFI Mercury Grand Marquis. Well, I'll be blunt, being as curious and hands on as I am, I thought I should try partially disassembling the engine so that I could give it an original condition cleaning and efficiency make-over.

Well, it did not turn out that way. Apparently the vacuum lines and devices are installed wrong because now the engine backfires and runs rough. It also seems to be off balance, but I'm pretty sure that all that is the crankshaft pulley and balance damper, maybe.

I am not a mechanic but I do understand for the most part any mechanical or electric system process will a little research. But this engine's vacuum or air lines just keeps frustrating me more and more. Could you help me find a solution?

Sincerely yours,
John

A. Now you know why we say "If it ain't broke, don't fix it".

I would give you the diagrams you need, but the diagram depends upon the calibration code. There are five different choices. Your best bet would be to take the calibration code and go to the reference section of the Public Library. You can look it up in the and look it up in wither the Mitchell or Motors manuals. You can photo copy the diagrams you need and that will enable you to correct the vacuum and emission lines.