my friends truck is a 89 f150 5.0l 2wd automatic, and we just replaced the thermostat and all we un plugged was the Ignition Control modual and when we went to start it up it had a hard time starting and when we went to drive it, it has no power at all, all the stuff is plugged in. his driveway is on an incline and he would have it floored and it barely moves.

now we took it down the road quick to see if it just needs to be driven and nothing, so i unplugged the spout connector on the Distributor and it had a little more power but not much more. we didnt touch anything besides the thermostat, we did try seafoam and still nothing. it does need a tune up but when i took a wire off and tested the spark and it has good spark. we might try a tune up tomorrow.




is their anything else that could be causeing this problem?

 

Why'd you unplug the ignition module for a thermostat? I know mine is a 5.8 but its not in the way at all, maybe 5.0 is different. Are you getting any codes? you could try to unplug the battery, let it sit and hook back up to reset everything.

 

the ICM is on the Distributor and it was kindof in the way to get a wrench in to get one of the bolts off.
i was going to scan it today and try reseting stuff today.

when we let the truck cool down it had a little more power, then when it heated up it would have no power.

 

Did you guys maybe bump the distributor out of place. Bad timing maybe?

 

It could also be like my TPS. Worked fine, turned truck off, 5 minutes later, started it back up, and the TPS failed on me.
Not saying that is your problem, but it can do that and make an immediate change like mine did. Something to look for.

 

I'm having the same exact problem with my 87 4.9L. I just tore apart my intake manifold to put on new gaskets because the old ones were shot and put an intake and injectors in it out of a truck in the junk yard after I cleaned them up real good.

It starts bogging down real bad when I drive it. Started happening the other day when I was coming home, I went from 70MPH to 45 in about a quarter mile with my foot to the floor. I though my cat got all clogged up.

I got home tore the exhaust all apart and sure enough my cat was detroyed so I just hollowed it out and put everything back together. the truck still wasn't running right. I thought maybe my exahust manifold had slipped out of place since I had to take it loose to work on the intake manifold. I fixed all of that and as far as I can tell, its lined up right.

The engine and the cooling fluid was heating up very rapidly when I would test drive it around the block so I drained the fluid and flushed the system and put new fluid in it along with a new thermostat. I also gave it an oil change.

I pulled all the plugs, cleaned and regapped them and pulled the distributer cap off and cleaned all the contacts.

I also got several MAP sensors out of the junk yard and have gone through all of them. The truck doesnt want to idle very much only after its warmed up for several mins and its still pretty rough but at least it wont stall. I think maybe its that sensor but a new one is 60 bucks and I'm pretty short on cash and dont want to have to buy a new one if I can help it.

My TPS has a broken off bolt in the intake so its loose, Im going to try the other intake form the unk yard to fix that though.

I need help with this and I'm tired of throwing money at my truck only to have no results. I'm about to tow it to my mechanic if I cant get it figured out.

 

I have an update on my situation. I took it for a test drive around the block to show my friend what was wrong with it and when I got back (running time maybe 5-10 mins) i opened the hood and ofcourse it was pretty hot but the headers were glowing cherry red, something is seriously wrong here.....

 

Was the engine temp gauge not in the red? If not then that sounds like an exhaust blockage. Maybe plugged cat?

 

temp gauge was a little higher than normal but only slightly past half and the cat is hollow now, it broke apart couple days ago so i tore it off the truck and just finished hollowing it out, I dont know what else it could be im about to tear the exhaust back off to double check nothing is blocking it up

 

Headers glowing red, sounds like the truck is running way to Lean. Surely if the truck has an O2 sensor, I would be checking that. Easy way is with a DVOM. If you need instructions on how to check it, do a search under my username and it will come up.

Have you pulled codes? That would be a good start. I have several theories, but don't know which to explain until you post a System Pass check from the PCM.

Does this truck have 2 cats? Some do, some don't. But I know on 2 of my trucks, 1 lower cat was destroyed and on the 2nd truck, the upper cat was destroyed.

Let us know what you find.

also, when you pulled the plugs, what color were they? White, tan, sooty? If they are all white, chances are you are running Lean.

 

There was only one cat on it when I bought it and that was the only exhaust on the truck I had to build the rest of the system. There's an O2 sensor in the header y pipe no idea off it works or not its a jumbled mess of wires under the hood from the previous owner who was an idiot.

I just pulled the codes again on my older Ford code reader it pulled; 31- EGR valve control sensor fault and 82- air diverted solenoid circuit fault

It's been pulling these same codes ever since I bought the truck almost a year ago

When it first started to act up I pulled over to check and the wires to the O2 sensor were against the headers burning but as far as I could tell it was just the insulation around the group of wires that burned but I'm about to go check

 

Oh and the plugs were pretty much slightly covered in like a white to vanish soot but nothing significant I figured it was just natural build up

 

I had a similar problem, but not with the headers glowing red. My exhaust was so hot coming from the end of the tail pipe, that when I ran the back side of my hand over the outlet, it caused the hairs to frizzle!!!!!! I traced it to the TAD/TAB solenoids. When I disabled both of them(Knowing this wasn't the correct thing to do, and I now have it corrected) and the exhaust cooled down and it quit throwing that darn "Code 41 - No O2 sensor switching detected/ Running lean". You may want to try this idea. I simply removed the vac line from the Vaccum Resevior and plugged the end to the vac cannister. Not perfect, but it helped to troubleshoot what was wrong.

If the EGR is malfunctioning or staying open, it can cause it to run Lean as well. Open, it creates a vac leak. Someone flame or chime in if they can better explain. You may want to be sure it's not leaking or that the plunger is working correctly. Also, if the EGR is malfunctioning, then it can cause higher combustion temps which can lead to detonation.

Hope these ideas help and let us know what you find.

 

well i plugged my scanner in and when i did the engine running test it ran fine with all the power you wanted then when the test finished it went to crap. i got a code for the TPS so we tested it and it did test a little bad so we replaced it. when we got the new one it it ran fine then when it warmed up it went to crap. we cant even do over 15mph. it does have an exhaust manifold leak but that shouldnt really cause this to happen. we took it to a shop that my friend knows the person and are having him look at it. its actually his grandpas truck so they dont have the money to keep replacing stuff. well at least me and my freind tried, also when you would pull the oil dip stick out, it would be smoking cause it was hot. the whole engine was hotter than normal. but i never thought about the cat being plugged.

 

well my friend got his grandpas truck back and they said the timing was off. which i dont understand, how does the timing being off make the truck run like crap but when you plug the scanner in it runs good. also when it warms up it runs like crap aslo. i dont know i will tell my friend to watch the truck and see if it runs good.