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LoriMaury Kimbrough

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After 104400 miles, my truck appears to me having its first mechanical problem. It's an intermitent problem so we are having a heck of a time trying to figure out what it is.



It will sometimes hesitate on acceleration even when the engine is at normal operating temperature. It seems to happen most when you first take off, like when shifting from 2nd to 3rd. My truck has a manual tranny btw. We noticed it the most when we were coming up a 6% grade. We were going about 50 and if I left the truck in 4th, it would really sputter, downshift to 3rd and all was well.



We've hooked up the AutoXray and recorded the engine performance while driving. Of course, it didn't do it one single time while we were tracking. Everything tested fine. It passes all tests the AutoXray can do.



We've cleaned the MAF sensor and that didn't make any difference. We are stumped. It's been happening for a couple of months and during that time we've purchased fuel from several different places so I don't think it's a case of bad gas. We can also go days and it won't happen at all.



We went to Texas for Thanksgiving and it didn't happen at all. I told the hubby that meant that even my trucks wants to live in Texas.



I really hate to take it to Ford and pay them $100/hour to hook it up to a computer and find nothing. With my luck, even if they did take it for a drive, it wouldn't happen.



I know it's a vague description, but it's really hard to describe. I would appreciate any direction for where we can look next.
 
Fuel injection needs cleaning?? Could be a dirty air filter(I know you take good care of the truck) Or maybe in the ignition, but I don't think so if you can drop a gear and it runs fine....Bob
 
Last edited by a moderator:
How old are the plugs? mine does that as well and is a manual transmission. It almost has no response for about 2-3 seconds then accelerates just fine. I thought it was the plugs so I was gonna switch them out in a few weeks.
 
Did you recently have the plug wires dine? I had one car do that 'cause the plug wire was too close to the exhaust sensor!

good luck Ed
 
The plug wires are original, the plugs are probably 70k miles old. We've talked about doing the plugs, wires and coil. Guess maybe that's what we'll do next. Even if it doesn't fix the problem it's not like it's a waste of money.
 
when we were coming up a 6% grade. We were going about 50 and if I left the truck in 4th, it would really sputter, downshift to 3rd and all was well.
Click to expand...



I would suspect wires. As it seems to be at a certain rpm and load. Might do plugs also. I would wait on the coil. Also I would unjack all sensor, ecu managment harness's, and plug them back in. Could be alittle corrosion.
 
You said brand new K&N ????? did you oil it ??? I bet there is oil on the wires in the MAF now..



Todd Z
 
Filter came oiled and it was put in at the same time we cleaned the MAF. So the problem was happening before the put in the new filter. To be fair, it did have a K&N in it before but it had been a long time since it was cleaned and oiled and when we started having the problem. Why did we change a lifetime filter you might ask? My only answer is...'cause the hubby said so and it wasn't worth the argument.



Once cleaning the MAF didn't work, my thoughts went to fuel filter. I think we changed it at about 75K, but don't remember for sure. I know it's been done once. Hubby is thinking plugs and wires. He says it's not fuel because you have to be moving for it to happen. You can rev the engine all you want and it won't do it. Put it in gear and go, and there it is.



So I'm thinking we'll do plugs, wires and fuel filter. Even if it doesn't fix the problem, it's probably time to do it anyway. However, I don't really want to do it all at once because then we'll never know who was right if one of those resolves the issue. Can't pass up an opportunity to say "told you so".



Thanks for all of your help.
 
I am still betting on a fuel system problem. Could be filter, bad fuel, failing fuel pump.



If it were mine, I'd change the fuel filter right now. 30k is a long time, especially with the crap gas we have around here.



Of course 70k on the plugs is a lot, and so is 104k on the plug wires.



For sure, you have three maintenance items that all need to be addressed anyway.



Good luck.
 
Sure sounds like you have a misfire. Put some plugs in it and a new set of wires and be done with. Get OE plugs and go with Denso wires, absolutely nothing to gain going with high dollar performance wires. I wouldn't waste the money on a new coil unless testing showed it was failing.
 
And the winner is.......sparkplug wire.



Saturday, the problem got really bad so I took him to Ford. They did their test and found that there was a misfire on #4. Since I had already ordered plugs and wires, and there was no way I would pay them the $450 they wanted to replace them, I had them put on a temporary wire. I also had them change the fuel filter since they were recommending it as well.



So now he's running like a charm and tomorrow he'll get his new plugs and wires.



After 104k miles my first problem turned out to be something I should have replace a while ago anyway.



Thanks for your help.
 

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