i have a 95 f150 that loses power after it warms up. i can be at a red light and when i take off it barely moves even if i have the pedal to the floor then all of a sudden it will take of like a rocket. the engine isn't even revving so i wouldn't think it was the trans. Even going down the hwy. the power drops off for a min. then it picks back up. the CEL does come on but it seems like it only comes on after it picks back up and it never stays on long. i have had 2 different shops check it out and niether one could really tell me anything. I have replace TPS and did tuneup on it. all this was done atleast a month before this started. I would REALLY like to get this fixed before i sell it and get a newer f150.

 

put a scanner on it and see what the koeo and koer tests say. it should still have codes in it. how many miles and what motor? and what plugs did you use?

 

did that. no codes came up. it is a 302 with 152k on it. the plugs where motorcraft and where gapped at the right gap. it has some backfire but the fuel pressure was ok and the timing checked out ok too. i have owned many ford products with EFI 5.0's and have never had this happen.

 

are you running it with an ethonal blend fuel? i'd change the fuel filter first. also possible iac. and does your temp gauge read normal?

 

temp. reads normal. fuel filter has been changed. i disconnected the mass air sensor and the truck ran fine after that. i'm going to replace it and see if that might be it.

 

The EEC-IV trucks aren't very smart when it comes to scanning the codes. They have 2 forms of operation, open and closed loop. Something is causing it to malfunction in closed loop. The system doesn't go into a full closed loop state until the engine reaches operating temp.....which is why you don't get any problems until the engine warms up. Un-plugging the MAF simply defaults the system back to open loop......where it seems to run fine. However, the MAF may not be the culprit...... It could be ANY of the sensors that function in closed loop......O2, ECT, ACT, TPS?? I know you said you replaced the TPS, but check it anyway. And why did you have to replace it?

 

i had the trottle body off cleaning it and thought since i had it off i would go ahead and buy a new one. what is an ECT and ACT? not familiar with the short version of some of these parts.

 

Engine Coolant Temp and Air Charge Temp. There's a little more to changing a Throttle Position Sensor than just putting a new one on. You may want to explore this a little more. Can you put the old one back on?

Personally, I've never had a problem with changing them out. But every manual says never to mess with them.......so there must be something to it.

 

no i done threw the old one away. the tps swap was done 6 months ago to be exact but that doesn't mean it couldn't be the problem. i will maybe try ajusting or replacing it.