94F15090GT

K been over all this , 94 F150 5.0 302 , new everything almost , all new seals , new oil pump , water pump , all new hoses , new distributor cap , new ignition rotor , new plugs , new plug wires (tried 3 different sets) , now new fuel filter and new coil , all new vacuum hoses. Im still getting hesitation and jerking under light throttle just when you are barily giving it gas cruising along , all other times its fine. Please does someone have any other suggestions for me to try or anything?

motorhead6

Just a shot in the dark but I had a similar jerking problem when I was driving. Wouldn't happen at Idle only when the vehicel was under load. It was the TFI-IV or distributer stator (PIP sensor). Its located at the top of the shaft of the distibuter befor the cap. It comes off with just 2 screws.

foxey

is it an automatic or 5 spd?

94F15090GT

It is a automatic , but it doesnt feel transmission related , tranny shifts fine in all gears sounds good, I just had the whole transmission out when I had the motor out of it drained the converter , all new seals in it. It feels like the engine, heres basically what describes it , from 35mph+ (you can feel it at slower speeds then that if you are babying it) but from 35mph+ when you are just barily giving it gas it starts jerking and bucking like its running out of gas , but when you push the peddal down its fine. I had some codes before , it was the EGR valve and the TPS sensor. Replaced both , but when I replaced the TPS sensor I just took another throttle body from the extra engine I had and swapped throttle bodies. I was reading somewhere not having the TPS adjusted right could cause it to jerk and buck like that? I didnt adjust the TPS that was on the extra throttle body I put on I just left it how the factory had it. What do you guys think could that be my pain in the *** causing this?

aliens8mycow

Mine's still doing the same thing too, and I've also just about rebuilt a new truck along the way.

One thing I noticed, is that when it idles, you can hear a 'burp' (for lack of a better word) at the tailpipe. Like it's loading up or missing just a touch. The burps seem to be fairly close to the rythm of the jerking when it's just off idle while driving like you decribed.

I'm starting to think it could be incorrect timing? I'm about 2 weeks away from a new longblock - hoping that the issue goes away in the process, but if it's the PIP or some other 'external' component, it'll go right back on my longblock...

94F15090GT

Well , Im putting a Timing light on it this weekend , and Im going to try to set the TPS sensor and adjust it , and set the idle , Im thinking about just replacing the whole distributor with a new 1 when I go to time it this weekend , the disty on it was off another motor and has a little green corosion down in it. It keeps doing it after that I have no clue next lol probably just take it to ford and let them get me up the *** i guess lol

aliens8mycow

Sounds like you're as frustrated as I am! I just came in from checking my timing - it was about 12*, so I set it back to 10* as the factory recommends. I will be taking my son on some errands later, so we'll see if it helps. Just idling in the driveway, it seemed like the burp at the tailpipe while idling was gone (keeping my fingers crossed). If you have a factory muffler, you may not be able to hear that, but my glasspack sounds off quite clearly.

If the timing doesn't cure it, I'm hoping the new motor does it for me... the longblock swap is due to a worn out crank or rod bearing knocking like crazy and losing oil psi. Maybe I'll get two for one!

aliens8mycow

Well, I did some driving tonight, and I truly think that getting the timing right might have helped. I actually planned my routes around speed zones that usually caused the shakes to be the worst. Only one brief time did I feel like it was doing it at all, and that might have just been in my head...

I don't want to get too excited yet - I've had the feeling of success before, only to be brought back to harsh reality over the next couple of days.

94F15090GT

I think its got something to do with the distributor man hell thats the only thing i havent really touched yet. Either that or the TPS , or the computer , theres nothing else it could be.

aliens8mycow

I don't think it's the TPS - mine is brand new and was adjusted according to spec. After driving to/from work today, mine is still doing much better after setting the timing.

I think there is still a slight (very slight, maybe my imagination) shudder there... The timing pointer was bent up on my truck, so after trying to get it straight again, I'm not sure if it's totally accurate.

I'm not going to get into the PIP until after my rebuild - if it still feels like it shudders, I'll look into the PIP.