Mygrey89

So Ive been having this problem for a while and Im running out of ideas..

when the truck is in P or N it idles fine..sounds good..as soon as I put it in drive it runs like hell..kinda feels like Im running on 4 cyls not 6.
89 f-150 300 s6
new plugs, cap, rotor, wires and coil..

Any help would be appreciated

Steve

transmaster

sounds like you might have bad injectors or the cold start system is not shutting down. The later can be caused by a bad engine temperature sensor. Do you sell raw gas in the exhaust? You have an OBD1 system pull the codes and see if there is anything there. Autozone will read the codes for you for free.

Mygrey89

replaced three injectors yesterday..havent check the temp sensor Ive also run the truck on straight injector cleaner..hooked up through the schrader valve and hit the first inertia switched..replaced the three injectors that had cracked tips.

AuroraZero

Check fuel pumps. I had a bad one and it made it do this.

Mygrey89

Ok so I replaced the engine temp sensor on the thermostat housing and still a no go..still runs like hell when in gear...have the other sensor that is for the head but Im not quite sure of the exact location of it..

Secondary thought here..if the bearing in my water pump is shot..would it cause the kind of problems I am experiencing?

Have done fuel flow rate check..not sure if that would suffice as a fuel pump check..got between 45 and 50 PSI at the shrader valve...but I do have an aluminum gas tank I just bought with a pump in it so Ill swap the tanks on monday and see how that goes...thanks for the replies..open to any more suggestions or questions about what has all been done to the truck lately

ridge903

Sounds more less to me that you have a vacumm leak somewhere. Assuming that this is automatic. As soon as you are shifting this thing into gear and the torque converter picks up the load it starts to run bad and act goofy check the vacuum system to make sure you dont have any vacumm lines that are broke or have come loose