Hello Scotty,
I am considering buying a 2006 Ford F150 with 148K miles for around $2000 from a private party which has the following description:
The seller knows very little about the truck and wants to just get rid of it. The only additional information I was able to get is that "slow" means it doesn't go beyond 20mph and that the truck was bought in an auction in 2017. I have worked on my own cars(Toyota) a lot, but I have no experience with Fords. Should I get it?
Could be a very simple fix. If the throttle body is full of carbon it will get stuck wide open and the engine goes into “limp mode” so you can safely get off the road without rapidly accelerating into whatever is in front of you. You’ll see an illuminated wrench symbol in the instrument cluster.
If this is the case a few squirts of throttle body cleaner into the flap on the throttle body will release the stuck throttle and you’ll be up and running.
Thanks Mike for your response. They had the truck diagnosed at a garage for 400 and were told the PCM needs to be replaced. You'd think if it is as simple as a stuck throttle plate, any average garage ought to be able to pick that up since the throttle position sensor would throw a diagnostic code.
If indeed the PCM needs to be replaced, what am I looking at in cost?
I had this same issue (intermittently) with a 2006 Expedition with the 5.4 Triton 3v. I can’t remember the code it threw but I had a garage try to sell me a PCM. (PCMs rarely ever fail). This was a common problem I found in a forum back when it happened to me and after I cleaned the throttle body it never occurred again in the 3 years I drove the expedition until i traded it in.
if you know the guy well, ask him if the wrench symbol is illuminated and if it is, I’d just go see if a couple of quick shots of throttle body cleaner will do it.
For PCM repair you’d have to call around for an estimate they’ll probably quote you about two hours labor. To remove and replace a PCM takes about ten minutes it’s on the passenger side firewall and easily accessible. The most time spent for the repair programming the PCM to match the vehicle.
That is something you can actually do with a program called Forscan and a connector for your laptop computer., but it’s a little complicated to cover in a quick forum post. I’ve used it to reprogram salvage modules and the best part is the software is free and Ford provides the necessary codes online for free as well.
If you have a garage do a PCM change they’ll have to program the PCM. The truck won’t start without it. The self programming is if you do a swap out with a salvage PCM at home.
Got a chance to check out the truck today. Its a 4.6L V8. It did show check engine light but no wrench symbol. The trottle plate was not stuck open. The car idled real rough at about 800 rpm on cold start; fairly obvious that it wasn't firing on all cyls. Revving up, it barely got to 3k rpm. On my OBD scanner, I got codes P0352-P0358 - bad ignition coils. The owner states that he got the truck about 9 month ago as a fixer upper - it was dead, not starting at all. He had the coils and the PCM replaced at a shop and that got it to start, but run rough as it is now. He took it to another shop recently and was advised the PCM needs replaced again and reprogrammed.
It was a cloudy rainy day so I left without exploring further. I am thinking of going back in better weather. I am at the end of the road with my basic scan tool(MAC). Perhaps I should get Forscan and an adapter to help with troubleshooting?
Dang. I Was really hoping this would be the simple carbon buildup on the throttle body issue for you.
The coil packs and the plugs are probably due for a change if they’re original.
However a plug change on these engines is “fun” to say the least. look up the Ford two piece spark plug issue to see what you’re in for if you buy the truck as I’m pretty sure the 4.6 has the same plugs as the 5.4. I’ve done the change on 3 engines with them and have about an 80 percent success rate getting the plugs out following the Ford TSB without them breaking. there is a tool from Lisle that makes it fairly easy to retract the piece stuck down in the head if the plug breaks. Have that tool BEFORE you start if you decide to take this on.
Following your comment, I have been reading up on the Ford spark plug fiasco, because I would like to do a compression test on the cylinders. As per Ford TSB 08-7-6, the affected plugs are in the 2004-8 Triton engines with 3 valves per cylinder. Luckily for me, this truck has a 4.6l 2V engine - normal plugs! I'll probably do a block test for combustion gas in coolant to check for blown head gasket as well. I am thinking if the engine is mechanically sound and has only ignition/PCM issues, it is probably worth getting it and solving those problems.
I noticed online there are a lot of outfits selling PCM's pre-programmed with your VIN. They claim plug-and-play. What do you think about those?
The programmed PCM should be fine. They get the data right from Ford to program the hexadecimal data fields.
Try the coils and plugs first before you put in the PCM in case you don’t need it, once you open the package I believe you can’t return them.
If I had an opportunity to pick up an F150 for $2000 I’d jump on it. I bought an 07 lariat 4x4 two years ago to replace one I lost in a collision and it was $14,000 and that’s the best price I could find within a couple hundred miles.
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One thing I forgot. The trucks been sitting for quite a while. Fuel has probably separated/ destabilized. Before you tear anything apart; if the tank level is low just put a few gallons of good fuel in it.
That's a nice video showing the basics of how to troubleshoot ignition wiring. I think in my case somesting strange is going on. I got codes P035X for seven out of 8 cylinders. Yet the engine starts and idles, albeit somewhat rough. Judging from the sound, I guess it is missing one or two cylinders. With seven cylinders not running, I doubt if it would even start. The spark plugs and coils are new, so maybe the PCM has these codes set spuriously.
Got a chance to look at the truck for a little while today. Did a block test for head gasket leaks. It passed. Could manage to do compression test only on cylinders 1,2,3,6 and got 160,125,150,155 psi respectively. The other cylinders were difficult to access and I ran out of time. The spark plugs didnt give me any problems - they were not the prolematic 2-piece type. I would like to do the other cylinders as well, but No. 2 is already raising a concern. Is that enough to explain rough idle and loss of power? Any thoughts?
That 120 psi cylinder could be an issue. It should be within a about 10-15 percent of the max cylinder pressure. In this case no lower than 136 or so.
To see if it’s worn rings a teaspoon of motor oil put in the cylinder before the test should raise the pressure if it’s warm rings. If nothing changes it could be the valves.