I have a 89 f150 5.0 auto w/od 4x4. After it warms up it will shudder on take off and before shifting gears. If I get on it the shuddering goes away? I just baught the truck and it has 124,000 miles on it. Any suggestions would be appreciated.

 

Has the truck been lifted?

 

I have the same problem with my 1987 4x4 302.
Check the following:
Vacuum leaks
EGR Valve, sometime the EGR valve can be cleaned up with some carburetor cleaner.
O2 Sensor
Check the coils, by unplugging one at a time until the you notice the coil that results in little change in the idle of the truck
Is it showing any codes?

 

only one coil and 8 spark plug wires.

you need to tell us a little more about truck.

did you try to do anything to fix it? plugs, wires, cap/rotor, air cleaner, fuel filter been changed?

 

No Lift. The only thing I have done so far was to seperate 7 and 8 plug wires. Looks like the cap has been replaced and the fuel filter.

 

if you do not know when than change them.

pull plugs and replace them.

replace air filter.

do the basic things first than worry about throttle body and other possible problem areas.

 

I finally got around to replacing the plugs, wires, cap, rotor, coil and air filter. I fired it up and it seemed to run better at first but when I took it for a drive the shutter is still their. All the old plugs looked ok except for #8. It was black and wet. I am going to check for codes next.

 

I would run a compression test on number eight. A down cylinder can play havoc with your vacuum. While you are there, you might test the others too.

Vince

 

How does your transmission fluid look? Also check your u-joints, I doubt thats your problem, but never hurts to check/replace them. Is your tranny an AOD, or E4OD? The E4OD will have an OD cancel light on the dash, on the RH side of the column.

 

Transmission fluid looks and smells ok. I have not checked the u-joints but I do not think they are the problem. My Tranny is the AOD.

 

I decided to reset the computer by disconnecting the battery for about a half hour. After the reset I fired it back up and it sounded like the miss was gone. I took it for a drive and it was 90% better. No shutter at take off and barley noticeable at 35 mph.

 

I had the same problem & did all the above and it was suggested here to check the universal joints. That's what it was - front & rear. Didn't change the carrier out but the problem went away immediately and she's now strong & mighty again.

Love this website....check your uni's

 

Had a shudder when shifting into overdrive gear on my 1994 F-150 XLT with the 5.8L auto. Turned out to be the torque converter. $650 later problem gone.

 

I'm not seeing any of these ideas addressing the "black and wet" number eight spark plug. I see a compression test in your future. If nothing else you will know what direction to go after the test.

Vince

 

blhowell,

I agree with the compression check. You said "black and wet". Was that meaning oily wet, or did the plug dry around the electrode after you had it out for a while? A common problem on the 5.0's is that #8 tends to scavenge most of the PCV gasses because of the location for the tap for the PCV, even when everything is running perfect. This tends to make it run lean, hot, and very subject to failure before the other 7. If the engine's got any significant blow-by, then the oily vapors will also contribute to carbon build-up in #8 too. I've seen many recommendations for relocating the tap for the PCV to the center of the plenum to better distribute the internal engine vapors to all cylinders. Now, what this won't fix, is possible burnt piston or failed rings. If you're lucky, it'll be stuck rings if ring related. If you're not, umm, I won't go there. A quick check if you don't want to pull the plugs, is pop the PCV out, and plug the hole, then disconnect the fresh air hose on the driver's side v/c and see how much blow-by there is. If you see smoking blow-by, I'd suspect ring or piston issues, and most certainly check compression. All cylinders should be within 25% of the highest reading. Your readings will vary with mileage/service/usage habits, etc. On my '92, I had about 200 across the board. But, I've never found a definitive answer as to what is good or bad, just that 200 on an engine with 135K on it is fantastic. If ya don't have one that's way out, you're pretty safe, or the engine's worn out if they're all low.