Why does by 1999 Grand marquis not start sometimes?

when it doesnt start, does it spin over and try to start?

No. When you turn the key it does nothing. But, let it sit overnight and it will start the next morning, every time.

I would check the battery and the connections make sure there is no corrosion and that the cables are tight.

I agree. I had the same thing happen to me with a camry I owned. After cleaning and tightening the cables it worked fine. I'll give it a try. Thank you

Don't have the dealer change anything. It's not a cost effective way to find out what is wrong. It is a way to get you out he door with a lot of profit. Narrowing down the items takes time and patience. - It starts every time for the dealer because something is heating up and failing. When it cools off, it starts. If you had waited in the parking lot, it would have started for you too. Open the hood and it will cool faster. -- Get the codes read to see if anything is pending. It could be that crank shaft sensor, so if you want to spend money, replace it. Relays either work or they don't. You might be able to swap them around if they are the same to see if it makes a difference.

Exactly! I thought about it and thought about it and decided to change the crank shaft sensor only. The heating up and not starting and the cooIing off and starting points me to the crank shaft sensor. I agree with you that the relays work or don't work. It will be ready for pickup this afternoon. Only time will tell. Thank you very much for you advice.

if it were a sensor the motor would still turn over. but since you said it does nothing when you turn the key it sounds like a power issue.

My '89 Crown Victoria was doing the same thing. It sounds to me like the ignition module is getting hot. Once they get hot the contacts inside don't work and the car won't even crank. Acts as if there is not even an engine in the car, nothing, nadda. After the module cools off the car runs normal until it gets hot again, once you shut it off, it happens again. Change out the ignition module and problem is solved. Now that 97 Gran Marquis has a 4.6 modular engine in it and I'm not sure where the ignition module is or if it even has one. If it's got a distributor then its got a module. If not then it's got a coil-pak and that might be where your problem is. Unfortunately I'm old school and don't know that much about the newer computer controlled cars of the past 20 years. They keep getting more technical every year but as much as things change, some things always stay the same. Something electrical is getting too hot and not working, let it cool down and it will work. I would check the coil-pak or if applicable, the ign. module. Good Luck, MrBlueOval / Kenny.

I had same problem with 99 grand marquis. had to play with it to get it to start. leaving the AC and other electrics would eventually start. dealer had car 7 times and cost me over 1500 dollars. After 3 times ask them to replace the starter relay but the Ford mechanics said there was no relay to replace. they put in three new batteries, new starter and solenoid, ignition switch, new neutral safety switch, checked all electrical parts and still had this no crank problem about every other day. wife couldn't go alone int the car. Finally I went to alltech and got a Ford bulletin written about no crank, but was only given to Ford mechanics. The bulletin said problem is burnt or damaged relay. showed it to boss man at dealer and he put it on his desk. when I went back for my car they said it needed a new battery. The bulletin still on his desk and not moved. I am a pretty good mechanic and electrician but can't physically do work on cars, but I located a relay box close to the battery which has 2 high current relays. I removed the smaller one and the car would not crank. I went to local auto parts and got a new one (in stock) cost $12.00 PROBLEM SOLVED!!!!!!! FORD part # FOAB-148192-AA Cost 12.00 an took 20 seconds to unplug old one and plug in new one.. I will be writing FORD about this and the $1500. JIM C.

I have a 199 GM as well. Similar problem, but mine does not start when cold. First time, ALL electrical was dead. I had to manually unlock the door to get to the hood release. Then I "wiggled" the fuses and relays near the battery and the car started fine. Twice after that the car would not start, but interior lights and power door locks functioned. I popped the hood, "wiggled" the relays and fuses. The car started fine. This "may" be related to heavy rain/water effecting the engine compartment. Two of the three outages happened in the middle of heavy rain and one a day after rain. Reading other's comments I'll replace the relays and wait to see if it happens again. My battery connection/cables are pretty solid, but I'll clean them up and re-install them as well.

RELAYS - RELAYS - They get hot or too cold, usually too hot. THE RELAYS ARE CHEAP LITTLE CUBES WITH DIODES. My car a 2005 MARQUIS DOES THE SAME THING. I switched the horn relay to the fuel pump start-up relay position. SAME Part # in fact, 5 of the smallest Relays in my under-hood box are identical and interchange. They are about one-half-inch by one- inch rectangular-shaped black cubes with 5 prongs. 3 other larger relays are also the same part #'s and are about one-inch by one-inch sqare-shaped black cubes. There may be one other Blower motor relay square-shaped also with a different part #. There is a map (diagram) in your owner's manual showing the square and rectangular-shaped relays and their function descriptions. Be sure to compare your old relay with the one you are buying. I can tell you for SURE that many part books show the WRONG relay for some replacements....A lot of catalogs show the larger square relays for what should be the smaller Rectangular relays...Buy the BEST quality relay you can get. I recomend Standard Motor Products (SMP). They (SMP) make two (2) qualities. Don't buy the SMP part # ending in "T". For example I bought 5 new SMP relays, part # RY116. The cheaper economy part # is RY116T. The price difference is about $1.. Go to the dealership ONLY for recalls or to buy a new car or they will sell you lots of parts and labor you don't need. Hope this helps someone else, GLENN (PontiacManiac) Both of the rleays should cost more than $10.

I have A99 Mercury Grand Marquis and the start of don't do anything but click when I turn it over