i have a 93 f150, 302, 141.### miles, Last night on my way to work, just as i was pulling into the parking lot at a slow speed thou i did not catch the speed, my truck suddenly started shaking like crazy and then shortly after it Acted like it was gasping for air, Choking, after it did that, the truck went back to normal..

It just started this, when i got back home, pulling in, again slowing down, it suddenly did it once more, shaking badly then a sudden loud gasp for air and it returns back to normal.. it would shake so bad for those few secants, making you think the motor was gonna jump out at ya..

not sure if its safe to drive right now? i dont want to make it worse.. the bad part is, its the only running truck i have right now for work.

 

Check engine light ever flash or stay lit?

My guess is weak alternator. Weird, I know. But mine did that years ago and I just happen to have been driving at night with the lights on and everytime I would slow down to make a turn or stop at a light or stop sign, it would go bezerk. Well, I looked down at my volt gauge and saw it dip low and then go crazy. As I gave it gas, it would come right out of it.

It's worth checking, especially if it's a 2G alternator. Check simple stuff first. It wouldn't happen when cold, but after the alternator had warned up, it went crazy. Had bad diodes in it.

 

the vault meter on the dash does not budge, Just stays at its normal point, as for a check light, it only comes on when you turn the key in acc then turns off when shes live, lol

other wise ive been noticing some rough idles, sometimes close to her wanting to die but she pulls her self back out of it.. or other times when shes a little hesitent on power, or taking a bit to speed up or needing to press a little harder on the gas to get er to go.. not sure if all this might be related or not. or if a sensor could be going out..

 

Can anyone point me in the right direction? What to check out.. sensors.. etc.. could it be a bad sensor a bad 02? Or vacuum line split? Maybe a bad fuel pump regulator? Im kust throwing random ideas so I know where to start

 

Slow speed is your clue. Coasting or slowing down. Check for stored codes. Otherwise, get a Good DVOM on the battery and see what volts are being put out after the engine has ran for at least 30 mins. Turn headlights on and blower on high. If your not seeing at least 12.7 or higher, I'm betting weak alt, or battery. When all the sensors get close, at, or below 12 volts, your gonna get some crazy performance.

Also, do you have a 2g or 3g? The 2g has the 3 line connector that gets loose and if it gets hot, create resistance the hotter it gets. Hot enough for a fire. If the plug gets loose, it can mimic a weak, failing alt.

 

well it was 12.7, its getting worse, the truck is shifting harder, need to press harder on the gas to accelerate, sometimes it wants to lurge forward when shifting gears, at times it will have a rougher idle, almost dieing.. i dont have a pressure tester for the Map sensor, starting to wonder if it is the sensor going out? maybe bad spark plug?

 

Mine does exactly that same thing.

Punch the throttle and she'll run like hell. At idle the engine sounds like it has a nice cam, except for every couple minutes the RPM's start falling off and I can hear it gulping air as the PCM opens the IAC valve to compensate.

I know what's causing mine and probably yours too... check for a vacuum leak. Mine's right there at the upper intake where there used to be a vacuum line to something or other. I had it capped but the cap cracked and fell off, as did the last 3 I put on there, so I'm fixin' to weld that steel nipple closed and fix it for good!