im having two problems with my 90 f150 with the 4.9. lack of uphill power, 50mph on steep grade tops in third, i have a automatic trans, and it keeps dying on cold startup. it will start up then die and ill have to restart 3 or 4 times to keep it running, once it finally runs it great the rest of the day. i check the timing, with spout out and set to 10 degrees, replaced the plugs, wires, rotor and cap. replace the iac and tps. there has to be something that regulates the way it starts cold thats not working right. i havent check the temp sensor on the thermostat housing yet, thats my next step. also i checked the vacuum and it holds 18hg. i also checked the egr and it seems fine, no leaks. its got me stumped.