workinman

hello i have a 1996 f150 4.9 inline6 w/manual 5 speed eddie bauer edition w/ac approx. 205,xxx originally bought by a company has been very well maintained . the issue i am having is about 60% of time truck will start but then shake and die immediately after unless reved for a few seconds when i apply gas the truck runs good but if i stop at a light it will make really loud rattling noise sounds like its coming from tranny /rear motor area and car shakes sometimes it takes about 5 minutes to get started after several attempts also as im driving down the freeway sometimes the car seems to suddenly lose power and if i push the gas in it doesnt change until 5/6 seconds later the other day when i was driving to work what usually only takes a half tank went through a whole tank. on the other hand sometimes the truck runs normally. recently ive had the 2nd cat.conv. replaced not first because i didnt know there were2 and the shop neglected to mention anything to me new fuel filter oil full synth. plugs,wires,cap,rotor,harmonic balancer,starter,power steering,hydraulic lines for clutch egr valve solenoid dpfe sensor and a few vacumn lines and a few other random parts ive been using 91 w/fuel treatment for a while now to help clean it out. ive searched endlessley havent found an answer i took it to shop and had them run diagnostics for me came up with p1400 dpfe inop p0385 crankshaftpositionsensor out of 7 range b- circuit malfunction p0420 cat efficiency below threshold- bank 1 (obviously). before had egr code but that cleared. im thinking maybe a timing chain maybe iac maybe ckp. but i do not have a lot of money or time to for repairs i work from 5 am -8 pm long commute. just looking for some sort of a starting point. i miss working on my 68 things were simpler. only transportation if anyone has some good suggestions id appreciate it ive checked forum for other post but havent found anything similiar. theres no funny smells oil pressures normal oversized radiator truck doesnt overheat everything is good except the forementioned.im not the most experienced mechanic but i know my way around a motor and am mechanically inclined. at least i thought till this problem that i cant seem to pinpoint. please give me any input you think would be helpful. thank you for your time. have a great day and remember lifes too short to stress.

Aktech

What is your engine vacuum at?

Aktech

A P0385 "check engine light" code could be caused by: Damaged CKP sensor connector Damaged reluctor ring (missing teeth or not turning due to sheared-off keyway) Sensor output open Sensor output shorted to ground Sensor output shorted to voltage Failed crank sensor Failed PCM

workinman

to be honest im not sure how would i locate the engine vacuum my best guess it appears to be over my alternator it has lines that run to smog and fuel rail.

Aktech

Engine vac is usually measured at the brake booster. With a vacuum gauge. Sounds like you need a manual to help u out.

workinman

haha. i get it now you said whats it at not where its at ill try to get a gauge to find out sorry about that one. i couldnt figure out what a engine vacuum was i always thought it ran off intake.

Aktech

The booster hose goes to the intake. I should say unplug the hose off the booster and measure off that hose. If u got to buy a gauge get the one with the hand pump. U can test more with the hand pump one if u need 2. If you don`t have a miltimeter get one of those also. U may need one to trouble shoot the p0385 code.

workinman

ok so i plugged it in it was at 22 then it dropped to 20 and after that it was consistently at 21.i have multimeter too.

workinman

if you think it would be helpful i have a video of the sound im talking about from in cab when i was stopped at a light but i cant post it i would need an e-mail. and thank you for youre time and input hopefully itll save me some time money and headaches.

Aktech

Your engine vac is good. Test and/or replace the dfpe. Take the two hose off the dfpe and blow and suck on them. Do they leak or plugged?