|WYG|SS

ok i recently had a problem with my truck missing so i had intake cleaned out cause it had carbon up. so i had bought fuel injectors out of a 5.0l f150 and put them in while i had intake apart. so then my engine was running rich cause the fuel injectors were pushing in too much gas but truck ran fine. so i put old(stock) injectors back in and truck ran like crap again so i took two of the injectors i got out of the 5.0l and replaced the two cylinders i was having problems with #3 and #6. so truck ran fine then with 4 injectors at 12# and 2 at 20#. now ive noticed problems when im in gear and at a low speed my truck seems to shake like it is missing again but when i give it gas it runs fine, im almost thinking i might have another bad injector but when i pulled the check engine codes i got truck was running rich(which was stored from 5.0l injectors) and map sensor vacuum unplugged but i checked and every vacuum hose was plugged in. what could this possibly be?

i got a 93 4.9l f150 127,000 miles on it 5spd.

and can any1 help me find stock injectors cause summit racing has 15# for performance injectors.

farmer12

I was under the impression that the 6 cyls had 19# injectors like the v8s...but I could be wrong. If you need new stock injectors just go to a parts store, napa, autozone, checker...they could get'em for you no problem. I think you should get the correct set of injectors in it, clear the codes and go from there. You might have a pile of plugged injectors on your hands. To clear your codes just unhook the battery for bout 15 mins then run it awhile and get it checked again.

dr_bowtie

why was the map sensor unplugged...this regulates fuel as well...

|WYG|SS

well the map sensor was not unplugged. is it the sensor on the firewall next to the blower motor? but the thing is advance auto wants 60$ each. i cant afford this. i dont want to go to a junk yard cause i dont know if they will work. i know you can test the injectors but their is a chance to fry the injector if you put power to it. im wondering if 15# would work without putting too much fuel in. that 200$ isnt a bad price for accell performance injectors.

dr_bowtie

more fuel mean lower fuel mileage....albeit the 4.9L runs rich already I dont think 15# injectors are teh answer...as stated I would look online to see if you can find stockers cheaper...

or call who ever had the Accel units and see if they offer stock injectors...

I am thinking of getting one of those adjustable resistors that piggy back into the MAP sensor to trim fuel...the MAP sensor is the little black box looking relay type thing to the right of the blower motor with a wire plug and a vacuum line...

this is how the ECM tells the injectors how to pulse...it gets the direct reading and coincides that with the TPS...those are the 2 most important sensors...the O2 is only read during loop mode..

|WYG|SS

yeah i was looking for stock. 12# but yeah i pulled codes again cause i started out in 1st and as soon as i let clutch out all of the way man did it jump really bad. and i mean bad. the whole shifter was moving back and fouth. i got code 128(manifold abselute pressure / vaccum sensore disconnected or damaged) and 179( HO2S sensor running rich at part throttle) maybe it is the injectors. i was thinking maybe it is cyl 6 cause i i did have a lot of carbon build up in that cylinder. but yeah i want to get them changed before winter with stock injectors.

dr_bowtie

a bad map sensor will mak it buck real bad...mine is starting to do that...

I was looking at adjustable map sensors and I found ford uses a digital signal map...this really screws it for adjustability...I was hoping to tweak the sensor to compensate for this...no wonder people hate fords speed density system more than any other...