Hello all, bear with me here. This might drag on for a minute. I bought my 1988 F150 about 2 years ago from my uncle. He bought it in 91 or 92. He drove it minimal miles. Mainly back and forth to work. He was the kind of guy who would fill both tanks then let it set. Then every 6 months drive it to the shop to get the fluids changed and say he takes "damn good care of his vehicles." With all that being said, he was an alcoholic and drank himself to death and didn't even start the truck for probably 2 years. The truck only had 72000 original miles when I bought it. So I got it for $400.00 cause it wouldn't start. To shorten things up, bad gas was the culprit. I tuned it up with new plugs, new fuel pumps and filters. After I got to drivin it around I had various "rotted" problems pop up. Rotted plug wires, rotted tires, some rotted vacuum lines. After all that, it has ran fine. My wife has taken over my truck lately cause its easier to watch our son when he is right beside her. She can barely drive anyways let alone her turning around to take care of a baby! Now onto the problem:


I drove it to work the other night and it had this HORRIBLE shaking/shudder. I thought what'd she hit now. I asked her about it in the morning and she said "oh, its been doing that for a couple of weeks now" Well I got stir crazy and went to hyperdiagnosing everything. It felt and sounded like a misfire so I changed the plugs. Which I did not have to do cause I but it Bosch +2 platinums. But I figured maybe I screwed something up. It has been very cold and icey here and I wasn't able to road test it much. So I have been driving it to work all last week. It felt like after it would shift in to 2nd gear that it would have a hard shudder. This is both in overdrive and drive. It does it in all gears after 2nd. If you punch it, it does away. It's kind of like in a manual transmission vehicle when you hit 5th instead of 3rd going 30mph. The whole vehicle shudders! So the trans filter/fluid needed changed so I did that last night. I was confident that I was experiencing a torque converter shudder. I even put in some transx. The trans shifts just fine, nice and smooth. Doesn't require any high revving, down shifts or anything. It works flawless. I do have an eshaust/emissions leak (the air injection reactor pipe) that runs from head to head on the back of the engine. On top of the pipe sets a check valve. It was rotted off. The tube itself is rotted through. So I guess the final
question(s) are..... please HELP! lol Tell me what you think it is and can be or if anyone has experienced these problems themselves.

 

A 88, is that a AOD trans? If so, it only shutters in D and OD?

I'd be looking to the tranny for issues. The converter on that trans is always locked up if the trans is in D or OD. But, if its not a AOD, forget what I said.

If you put it under heavy load in 2nd, will it shutter?

 

You sure this is Trans. problem? Sounds like it could be a timing problem or fuel. Why would you change spark plugs if you thought it was a trans. issue?

 

It is an AOD transmission. I do not think it is a trans issue. It shudders through all gears under a load. I am thinking it is an injector. I will get back with you all soon.

 

How did the plugs look?

 

1. start with the original problem, fuel, or things fuel related
2. check or replace the u-joints
3. check for excessive play (side ways or up and down) on the pinion shaft of the rear diff
thats all i can think of right now.

 

HOW MANY MILES ? and the bad gas could cause injector problems !

 

The plugs looked fine. The ones that were in there (that I put in when I first got the truck) was bosch+2. The truck only has 80000 original miles on it. I got it with 62 or 65 thousand if I recall. The engine, at idle, runs flawless. The engine shakes a little. I put it in drive, pull up againts a wall or tree and give it slight throttle. The hole engine shakes/shudders like it is being under powered. Similiar to when you hit 5th gear instead of 3rd going 35mph. In overdrive (which engages at 45) it feels like you "let off the clutch to quick" and starts bouncing resembling a manual. I have an AOD, im just trying to duplicate circumstances. My buddy, who is a huge gear head, says that it sounds like a plugged or bad injector problem. I dicked around with them today but with Fords Blower style intake, its almost impossible to get to the passenger side....anything really. The truck still starts/runs great. Like i mentioned before, I did have a huge battle with rotten gas. I haven't changed the fuel filter yet because I changed it 2years ago. That is probably my next step though. That's all I got for now. I hope to hear from you all soon! Thanks!

 

If changing the fuel filter doesn't help, I'd say you have a "dead hole" as in, you have a bad wire, the cap or rotor is bad, or a bad injector, and worse of all could have a burnt valve/piston.

 

What about a crossfire?
Are your plug wires run correctly?

 

I have the wires ran as best as I can out and away from metal grounding sources. The plug wires was new 2 years ago. They are a mother_______ to get in and out cause of the 45degree elbo at both ends. I am going to find some wires that are straight. See with the bad valve or piston I think I would have some more imminent signs. Im going to try the fuel filter and see. Thanks again everyone.

 

I just changed the fule filter and it was FILTHY! I mean black, with little dirt like pebbles. I poured it in a nowl and it looks like dark black coffee with the grounds still in it! The shuddering seemed to ease but not go away completely. I am thinking I got some of that chit up in my injectors. Anyone know of any damn good fuel injector cleaner/ What about the old 1 gallon of diesel fuel theory?

 

i think you can take the injectors apart and theres a little filter in them ?never had any luck with cleaner !

 

Hey. I am new to the forum but thought I would try and add another possibility. I have an '88 F150 giving very similar symptoms (5spd manual trany though). After many days of exhausting the standard tune up proceedures I considered it may be egr related (hunch from othere posts on this forum). I noticed at one point I had several holes in a pipe called an Air injector pipe (I believe) that runs from the first converter on the exhaust and eventually makes its way to the intake via T pipes, hoses and several other diversions. I have the pipe on order now but I tried to make shift a band aid until the part arives. It seems to make a noticible difference. Just a thought.

 

Thanks victory. I actually got one that is identical (I hope) to mine that I am going to put on and see.