MFI relay

If the service engine light is on, then I would say go ahead and get it scanned somehow or another. You can buy an OBD2 scanner on Amazon for like $20.00 and maybe cheaper on eBay. I would stay away from the really cheap Chinese Bluetooth ones though, as they only halfway work.

If the light is not on, then it is time to go with basic diagnostics. Here is a little guide that I have written:

Engines need several things in order to start. They need (1) fuel, (2) air, (3) compression, (4) sparks, and (5) 1-4 have to be on time, in the correct strength/amount. Unfortunately, when you get over 150,000 miles on any vehicle, any of those could be the problem. The most common causes are with (1) and (4).

I would start with simply listening for the sound of the fuel pump coming on. When you turn the key on, without turning the engine over, the pump should come on for two to three seconds. It makes a humming sound. If you can, get a helper to turn the key on while you listen for it. If you do not hear it come on, try tapping on the bottom of the tank with a hammer or other blunt object immediately after the helper turns the key on. If you then hear the pump come on, then you need a new fuel pump. Simple as that. You freed up the brushes in the electric motor inside the pump. This is a very temporary fix (might give you an hour or two of running time).

If you still do not hear the pump come on, then you need to check the fuses. There is a fuse box diagram attached below. The fuse box to look at is the one that's under the hood, along the left side. In particular, look at the fuses for "fuel pump", "ECM/TCM," "PWR Train," and "ENG Ign."

Just because the pump receives power and comes on, does not mean that it is pumping enough. We will circle back to checking the pressure output later on, if necessary.

If the pump is coming on, the next easy thing to check is for sparks. You can do this with a tester that is available at AutoZone or any other auto parts store. Here is a link for one on Amazon: https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6/ref=sr_1_3?ie=UTF8&qid=1501325755&sr=8-3&keywords=spark+tester

Basically, you pull the plug wire off of the ignition coil (also pictured below) and plug in this tester between the coil and the plug wire. Then get someone to turn the key while you observe it. If it flashes, then you have spark. Check all of the cylinders.

Let us know and we will go from there. There are more advanced tests that you can do for free or very cheap. We will go through them if needed.

Exactly what are you getting at the MFI relay? And have you inspected the wiring to the relay itself? It is possible that it is burnt or that there is a short somewhere along the way. I would check for continuity between the lead and the ground to check for that short. Any resistance less than infinity indicates a short in the wiring. I would also check for continuity between the terminals of the MFI relay itself. Again, resistance of less than infinity indicates a short.

Number 13 in the image below is what you want to check. I would go ahead and change it out, as sometimes (rarely but occasionally) a visual inspection looks good but the fuse is no good.

Okay, here is the information that we have on that MFI relay and testing. It does not say how much voltage should be getting there, just that it should be consistent. It also tells you how to test the relay.

No problem. I have got all the time in the world.

You will have to inspect the wiring and the connectors for issues. I would bet on the connector to the MFI relay being bad.

The local parts shop should be able to order some things that they do not have in stock. Also, you can always go to the dealer, or the junkyard/pull-a-part for things. Personally, I love Amazon. Com, rockauto. Com, car-part. Com, and the local junkyards.

That is what we are here for. Glad to help.

I do not think it will require programming. Just make sure that you get one with the exact same numbers on it. I am attaching Prodemand's info on the PCM. Pin #38 is for the MFI relay ground. You could probe that to see if the PCM is at least attempting to ground the MFI relay. If not, then replace it. If so, then the PCM is not your problem. Note: I skipped the info for the automatic transmission.