I test drove a '97 F150 yesterday with the 4.6, and it seemed to have a miss until the truck was warmed up to operating temperature. It didn't throw a CE light so it's obviously nothing serious, but what could cause this? It is the only thing really stopping me from buying the truck. Thanks

 

Possible causes for a miss:
1. Bad plug, loose or broke ignition wire
2. Dirty or malfunctioning fuel injectors
3. Low compression on that cylinder
4. Dirty or malfunctioning EGR

Most likely I think it is the EGR ports are clogged with carbon. That tends to be a very frequent problem. Fortunately, it also very easy and simple to do yourself. Takes about an hour, depending on how much other cleaning you do. I think that's it EGR from the way that you described it in relation to engine temperature. About the only way to check for this is to pull the butterfly off and try to run pipe cleaners through it. Good luck, and if you have any other questions, ask them.

 

Clogged EGR ports are like the plauge in the repair business. You'll clean them with air and BPC and Air andBPC and........Only to have in 500 miles the same damn code come back. Just replace all the lines for the egr if and when you get that code. I got that code almost 2 years ago on my sisters c280 mercedes, and after two MAF's, and EGR valve, a head gasket, some tranny work, two new valve covers and 40000 miles I still have the same effing problem. EGR flow insufficiant. I am ready to **** in the EGR valve

 

So basically you guys are telling me that the miss is not something that should seriously concern me? The dealership has a set of plugs and wires for the truck but have yet to install them. I'm new to the whole modular engine world, so I don't really know what to expect or look out for.

 

Have them install the plugs and wires, and drive it then. I'm not trying to persuade or dissuade you on the truck. I love mine, and will not get rid of it. However, I know that some things will happen, especially with 215,000 miles on it. But I don't care. I enjoy pulling it apart and finding out what's wrong. But don't get me wrong. In the miles that I've put on it, I've only had 1 problem, a bad plug. If you want a maintenance free vehicle, this may not be for you. If like giving your truck a little TLC every now and then, this is for you. As far as if that miss should be a concern or not, how many miles are on the truck? Everything is an easy fix except for low cylinder compression, or a burnt valve.

As far as modular motor, they're really not that different from 'regular' motors. Modular only means that Ford intended on having parts between the 3 main engins sizes interchangable, and that they could use the same tools to cast and machine all of the parts.

The same questions you'd ask for any other vehicle:
Does it use oil? Is it leaking anything? Does the tranny fluid appear milky or smell burnt? The list goes on. I take it that by having 'Stang' in your handle that you have one and are a pretty apt mechanic? If you've done any work on your stang (water pump, timing chain, hell, even plugs) then you'll be able to work on one of these trucks with no problem. The hardest thing to work with is the damn computer, but that's why this sight is the greatest thing on earth. No matter what problem you have, some here has seen it. Post your questions, and we'll see what we can do.

 

The truck has 150k on it.. Doesn't appear to have any leaks, and other than that miss it had no noticeable mechanical snafus. I do in fact have a mustang (1990, who would have guessed?) and have done about all the major things to it - engine rebuild, transmission swap (auto->5spd, best move ever), rear gears etc. Working on the truck doesn't scare me at all. Transmission fluid in the truck also smelled and appeared normal after driving, I made sure to check that. This truck used to be a department of conservation vehicle, so I feel very comfortable with the maintenance history of it.

 

Its not something that will harm the engine, but I would make sure the dealership fixes it before you buy the truck. There are quite a few things that can cause a miss and it can get expensive tracking them down/fixing them.

 

I agree with Johngs, have them fix it, but I don't believe it's a sign of anything serious. As you can tell from some of these threads here, the 4.6 is a damn good high milage motor if kept up. Good luck.