I bought the truck 2 months ago and it's always had kind if a rough idle..I had transmission rebuilt and about a week ago I decided to change tps sensor ...put one in ..it ran terrible..put old one back and it was ok the same as at first ran ok just a little miss. So next day I buy a more expensive tps sensor put it in..wouldn't run...put in another one...still won't run...put old one back in...still won't start ....I checked fire at plugs...it's good..I checked fuel it's 45 at rail..the plugs all have gas..the injectors are firing..open and close.I replaced egr.ignition module..distributer ..cleaned throttle body...checked timing (pulled off front cover) timing is fine ..sometimes it will kick once but never start..HELP.....I did check tps sensor with ohm meter and checked and replaced coil too...

 

Clean the MAF. What codes are you getting?

Maybe spray a little of the starter fluid in the intake and see what happens.

 

Is that a MAF or speed density engine? If it's speed density, replace the MAP sensor. Will it start if you give it a little gas? What about flooring it?

 

I tried starter fluid...and if you floor it to open it up or just barely press it still doesn't work...you get a small pop like it wants to once in a while but won't start

 

Yea it's mass air flow ...I cleaned it before but I'll try again and I'll check it's ohms and see if it's good...but if I unplug it wouldn't it start...cause it still dont...lol

 

1. Use only a Motorcraft TPS.
2. Check it's voltage output, in-circuit, KOEO, and ensure it's within spec.

MGD

 

Yea it's Motorcraft ...and voltage is within specs ...I even tried the original and it ran ok on it before ...still won't start...it tries sometimes just wont...got crazy cold and since then last week as soon I changed tps came out next day to try it and nothing since...

 

Roadie I don't have any codes really..but I reset computer after installing tps...hasn't ran since...only code is engine coolant temp and trans temp..but that's Normal because it's not up to operating temp to test

 

Post up the voltage output you read from the MC TPS - and how you measured it, under the conditions I specified.

Remember - it ran ( albeit poorly) before you touched that component - and not after. Personally - I don't think it's a red herring.

MGD

 

Mgd furst off thank you for your help..I'll recheck it again..but if it was tps wouldn't it still run maybe bad bud would still run.
.and I tried 3 and unplugged it and all ...still won't run.but I'll recheck it though....thank you

 

Is it possible I fried computer..testing tps or something ..

 

Ok..I can't start it to warm it up..but I did find something here...the signal from computer is fine and the ground from computer is fine...but the black wire coming out if tps...tested .5 which isn't it supposed to be .9 to1.4.. or us it because it's cold so it's lower...? Also I tested that by red probe to black wire and black probe to neg.on battery....tc