Hope you all had a Merry Christmas! So lately, I've been having a few weird things going on. One is this, when I floor it, the tranny shifts 5 to 8 mph sooner than it should, and when it does this, it consistently does it. Then it will just stop shifting early and rev all the way up like it should. Also, sometimes it shifts hard at wot, more often then not unless pulling a trailer, then it is always a smooth shift. Sometimes empty however, at wot you can't even hardly feel the shift, and from like 0-90% throttle it will be smooth. Also, under light to moderate throttle, sometimes, and even worse when the tranny (and engine) isn't warmed up, there seems to be a hesitation at certain speeds, and these certain speeds change on throttle and hill. I think this may be my base timing, because when messing with it it gets better or completely goes away, but it goes away at 11 degrees and I can't go past 10 whiteout pinging for some strange reason, I suspect my egr valve, it or something buzzes sometimes when I turn off the truck. But that's a whole other thread if need be. What's weird is this though. The other night it was doing the hesitation thing and shifting rough at wot, not horrible shifts but like you hit a small pot hole. I kept playing with it and flooring it then suddenly the truck ran way better, shifts were perfect and power was up. I recorded 0 to 60 in ~8 seconds, normally it's about 9 seconds, and this is a stock 96 5.8 f150 ext cab 4x4 btw, only has y pipe exhaust. Stock 3.55 gears and 235 75 r 15 tires. Sometimes, and only at 60 mph or above the mph needle will bounce about half a mile per hour to 1, witch points to vss. But it doesn't always, and if it were bad wouldn't it bounce more? Anyway, thanks for reading and for the replies. Oh and by the way, tranny fluid is only 10,000 miles old. And changed out all of it when I had my Tranny out, I think it was about 18 quarts. I took the tranny out to replace the front pump seal.

 

did you check for codes?..and if you did ..did you check your wiring harness by the cat on the passenger side for burnt wires?

 

I have no check engine light, and when I plug in my reader no codes. It's obd2. And I don't have any cats, bought the truck that way. So what harness are you talking about? O2 sensors? Or something else?

 

Vss

 

How do I check the vss to know for sure if its good or not?

 

Also, my truck engages and disengages rough, when I let off the gas it doesn't always smoothly disengage( I assume a solenoid for the torque converter or something) but every time I do it and tap the brakes, it's smooth as should be.

 

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The vss is magnetic so it may have metal on it from the diff. Take it out and see if u can clean it.

 

I did about 10,000 miles ago, it was almost completely clean, but I'll check it again. Any way to test the sensor though? Certain resistance, voltage, ect?

 

Anyone? I'd like to test anything that could cause these problems.