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Discussion Starter · #1 · (Edited)
Ive been having this problem for over a month now...
my truck has horrible acceleration everyday i start it in the morning, not in the afternoon or at night... however if i dont start it until the afternoon then it will do it... it always seems to be the first time i start it of the day and lasts the entire trip to work, school, etc...
It sounds like horrible hesitating/misfiring and my mother says it sound like a manifold leak. A few weeks ago it threw a couple codes and one was the crankshaft position sensor the other 2 were random misfires, and a class 2 communication malfunction. i replaced the cps and it didnt change anything...( i had this exact same problem about 6 months ago and when i replaced the cps everything was fixed and back to normal) but now it all started again...
also when im headed to work on the highway while this is happening, my truck will never shift into overdrive. i dont know if its something to do with the engine running so rough that it wouldnt have enough power to maintain overdrive or what??? it will stay around 2100-2200 rpms at 65 when its usually around 1700-1800...
again all this happens only the first time of the day that the truck is ran... after an 8 hour shift at work with my truck sitting the whole time, it runs fine when i start it back up...
driving me crazy guys,
let me know if you can help
thanks
new-plugs/wires/cap/rotor/fuel filter
 

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I have two thoughts on your problem, first would be a bad plug wire or it's not seated properly which can cause misfires. The fact that you had a communication fault, and the crank sensor fault leads me to a loose or broken ground? Just a thought.......
 

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Discussion Starter · #3 ·
i ran a voltimeter through the cps and the old one (both BWD brand) theres no way it could have went bad within 6 months and the connector had resistance which is good. i checked wires where applicable but couldnt find any loose wires, and its not like wiggling wires works because my truck does not do this at idle so i wouldnt hear anything.
but yes i agree with what you believe thats what i though when i saw that U1255-class 2 communication malfunction but i wouldnt know what other wires to check...
 

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If you can find a pinout of your ecm connector at the computer (42 or so pins), there are normally 5 or 6 ecm grounds that operate all of the sensors. I have seen corrosion inside of the ecm connector, which caused them to get an intermitant ground.

Another thing I got in the habit of doing, I buy a spare ecm for all of my vehicles as an exemplar. For your make and model you can get one for $50 or $75, swap the computer and see if it still does it. Your computer could very well be on the outs.

I have a 90' Lumina that started throwing all kinds of random crap out, that made no sense so I made the mistake of taking it to the dealer and they raked me over the coals for $4,000 in engine work i.e. fuel system, and electrical. I went to the junkyard and bought a computer for $25.00, and wouldn't you know my original computer was bad AND the car only had 10,270 miles on it.
 

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Discussion Starter · #5 ·
ive been googling for the past few days now and now luck on finding the pinouts for my ecm... i will look into my shop manuals for my truck when i go home this weekend but we have all the books for my truck except one which happens to be the only one all my problems occur in lol
 
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