I've been messing w/this problem for a couple of weeks now.
Truck has no power from a stop. Really notice it trying to go up hill from a stop. At first my egr stuck open, so I replaced it. Hoping this was the trouble before I knew I had a 172. It seemed to run a little better but not from a stand still. I ended up replacing the O2 sensor since I havn't for about 5 years anyway. But still have the same problem. The truck runs great once it's moving.
This is everything I have done to it in the past 6 months because one after another things kept going. Well it does have 250,000 miles.
95 F150, 302, K&N air filter.

new distributor, rotor, and cap.
new plugs, wire, and coil.
new oil pump, pickup tube, and oil pressure sending unit.
new IAC, TPS.
new EGR, position sensor, and PVC.
lets not forget the oil and filter every 3000.

The fuel pressure is within specs with koeo and koer and never lost any pressure well after 1 minute with key off.
Can't find any vacume leaks.

All my problems sound like this https://www.ford-trucks.com/tsb/full...?tsb=*98-23-10. Could the MAF be the problem? I did have a piece of grass or something in it and cleaned it out with MAF cleaner.

Any ideas?

 

There have been a couple of posts like this in the last couple of days. If I remember correctly, cleaning the MAF was the solution. It can't hurt to try it, as long as you are careful with it.

I was at Autozone today, and they have specific cleaner for the MAF. Looks like it is a spray deal like carb, and choke, cleaner, but it says MAF Cleaner right on it. I don't remember the price, but I don't think it was too far out of line. (~10 bucks, or so, if I remember correctly). I can't find it in their online catalog, but, I did see it on the shelf with the chemicals.

 

Thanks for the thought, but I did exactly that 2 days ago. I'm just wondering if I should replace the MAF anyway. I have read the other post with no help.

 

Sorry, I mis-read your previous post. It's sounds like you are way more aquainted with it than me, but (call me captain obvious if appropriate), how is the electrical system. Have you verified that your various ground straps are seated well, same for connectors, etc?

That MAF is spendy, I wouldn't replace it unless you know it's bad. Do you have access to a known good one that you can test with?

 

You could also try resetting the keep alive memory in the PCM by disconnecting the PCM connector or the batteries for a few minutes. Disconnect the MAF connector, leave it disconnected and take it for a drive. If it runs fine, it is probably the MAF sensor. If the PCM doesn't see a signal from a sensor it will either substitute a programmed value or infer the reading based on values from other sensors. This takes the MAF sensor out of the PCMs calculations.

This doesn't always work because there are so many variables, but it is useful to try if you don't have the proper diagnostic equipement.

 

Update.
The MAF is fine. After alot of thought, banging my head against the hood, and a couple of drinks, I put my finger in the oil fill on the valve cover. Low and behold I found a slight trace of coolant while wiping my finger inside. Could this be the cause of my problem? Lower intake manifold, head gasket, or cracked head?
If so, would it be better putting a rebuilt in due to the cost of all the new gaskets and what everelse needs replaced and time?

Any suggestions would be apeiciated.

 

I would guess that you are on to something there.

As far as what to do about it, it depends... Is the engine the original with 250K on it, or, has it been rebuilt/replaced fairly recently?

My truck has 203,000 miles on it. I only know the history for the last 600 miles. Right now, it seems to run very good, with good power, and it sailed through the emissions inspection, and tests.

Even though my engine seems to be in great condition now, if I have any major trouble (like a head gasket, loss of oil pressure, cracked head, or worse), I am going to put a long block in it. That will give me the peace of mind knowing exactly what is in there, and what condition it is in (or should be).

If your engine is fairly fresh, I think I would fix it, using a rebuilt head, if needed. Otherwise, I would long-block it.

I doubt that you'll spend anywhere close to as much as a long block would cost by replacing a head, if it is bad.

But, before you do anything, of course, make sure that there is really a problem in that needs to be fixed internally. (Captain obvious strikes again!)

If it were me, I'd do a leak-down test on the engine, or pay a garage to do it, so you can get more conclusive information about the condition of the engine, and pinpoint what, if anything is wrong internally. (I don't have any personal experience doing a leak-down test, but, from what I understand, quite a bit can be determined by it.)

 

No major internal work has ever had to be done to the engine. The valve covers have never even been off. I thought about trying some head leak repair additive just to see if it stops long enough to when the weather warms up. But before I do, is it possible for the throttle body to leak coolant? Asking because I noticed that the IAC gasket was soaked and dried coolant drips on the TPS. The coolant lines going to the TB are fine, no signs of leaking around them. Before I try any additive, I'm going to take it off after work mon or tues. to really check it out. It would be nice if this is the leak, easy fix.

 

First off, let me commend you on the maintenence of this engine...

IMO, getting 250,000 miles out of any gasoline engine is something to brag about.

When you say dried coolant drips on the TPS, do you mean that it is dripping on the TPS, then drying? Or, do you mean that there are coolant crystals being jarred loose, and that is where they drop? I'm wondering if the coolant getting on the TPS might be shorting it out, or causing it to misbehave at some positions...

Maybe corrosion in the TB is the problem. It sounds like it is worth checking out, and would need to be checked out anyway, even if you ended up replacing the engine. If it is not the problem, you'll have fixed something that sounds like it needed fixing anyway.

Back to the mileage on the engine... Like I said, I think 250K is a very good life for a gas engine. No matter how well you maintain it, it is going to wear out sooner, or later.

If the TB coolant issue doesn't solve the problem, I would still do the leak-down test, just to verify that everything internal is still working correctly.

Another thing you might want to do is check the exhaust for blue, or white smoke.

I'm assuming that your truck still runs a catalytic converter, and if it is doing its job correctly, I think it should be burning/vaporizing any oil, or coolant, before it gets to the tail pipe, so you won't have much visual clue as to what's going on.

I would temporarily replace the catalytic converter with a test tube, to see what the condition of the exhaust looks like, and go from there (if the problem is still present after you fix the coolant leak in the TB area).

As far as adding any fix-it additives ('mechanic-in-a-can') goes, I wouldn't do it. It only works sometimes, and when it does work, it only works temporarily.

It also tends to make a mess out of the components it touches, and when you go back to fix the problem correctly, you have to clean up the remnants of these additives.

I'm not a fan of Mechanic-in-a-can!

 

Call me what you want. But after thinking about this, I recalled removing the TB back in Jan to check the inside of the intake manifold. In the process I removed everything attatched to it. Put everything back together and started driving. I never thought to check if I properly reinstalled the TPS. Just noticed that it looks as if I installed it backwards. Hooked up a DVM between return signal and TP signal. Read 375 ohms with the throtle closed and 3.85 kohms wide open. I beleive that the readings should be opposite. I'll reinstall it hopfully tomorrow and then check the voltages to it.
As far as the coolant leak, I did add Bars leak stop because I think it was just a pin hole leaking into the valve cover then going through the blowby into the air intake then leaking through the IAC gasket. For now that has stoped.
Thanks for all the help. I'll let you know if this helps incase someone else has done this to.

 

Just to make sure that there is no misunderstanding in my previous posts, I was referring to myself with the "Captain Obvious" routine.

I hope that it is the TPS, that sounds like it should be an easy fix. (Crossing fingers)

As far as the coolant leak, I can't say that I get what you are saying. Does your system somehow have coolant lines plumbed through the valve cover? Or, am I just having a comprehension problem? (Those happen quite regularly to me for some reason...)

 

Sorry if it sounded bad. I only said that because I was calling myself a lot of names when I figured out what happened. Won't be able to reverse it until it warms up some more. This cold snap really stinks. At least the truck is getting me around for now, just hurting the mpg.
As far as the leak, I meant that it seems to be running a vicous cycle. Possibly leaking from the lower intake through the vlaves, into the valve cover, through the hose from the cover to the air intake, through the TB, One big circle. You would think that it should burn up, but not sure. After the truck warms up the white smoke stops. The smoke is only there when it is cold outside. When its warm, no smoke at all. But after adding the Bars leak stop, that vicous cycle seems to have stoped. No more signs of coolant in the oil fill hole.

 

I was just making sure that you knew the "captain obvious" wasn't directed at anyone but me. It's sometimes hard to tell the other persons intention without the body language, or tone inflection, that usually accompanies communication.
Sounds reasonable. Good luck with the TPS, and I hope the coolant leak doesn't turn out to be something major. I keep harping on the leak-down test, but I think that will be the best possible indicator of where the engine is in its lifecycle.

FYI, I thought my engine was in great shape (and, it was in terms of emissions, compression, etc). However, it turns out what I thought was an exhaust manifold leak was actually the #4 wrist pin slapping a bit in the connecting rod. So, I'm putting a Ford/Motorcraft long block in it now.

(Actually, I'm letting the local repair shop do it, as my garage isn't really set up to do it easily. I'm getting a 3yr/100,000 mile warranty (towing, and warranty repairs, at any Ford dealer nationwide), so that works for me. It hurts the old wallet a little bit, but I think this truck is a keeper, so I don't mind so much. I'm still saving around $20,000 over buying a new truck with the same capability.)