Will not rev past 3000 rpms

[Big-E]

After much searching I am stumped. I have a 97 XLT with the 4.0 SOHC motor and since i swapped out cracked T-state housing last night truck will not rev over 3000 rpms.. Usually its maxing out around 2500 rpms. This is with load in gear driving down the road and in P or N. (auto trans) - I have tested AFM and it tests out good. I drove car down to Advanced to pull codes (check engine light on) and it was coding for MAP sensor. Learning from this site truck really doesn't have a MAP sensor and when i disconnected the sensor on drivers side valve cover right next to dip stick no change happens.

I also notice no change happens when i disconnected the camshaft position sensor (in drivers side valve cover (closest to front of valve cover)) As of right now I am thinking it could be this but have no idea why it would fail after about 90 mins of the truck being parked to when i replaced part and put back together. It has 177,000 on it right now and i have owned it since around 70 and change.

If anyone could please shed some light on this let me know.

Thanks in Advance.

Big-E

 

[my98nnj]

MAF sensor

 

[Big-E]

MAF tests good and i swapped with another MAF from another explorer. Same condition. Ran up to autozone to have codes pulled. Only 2 show.. O2 sensor ( i got a bad downstream one) and the CAM sensor. Cam sensor makes sense since it controls timing. Should be in by 1 so i will find out then.

Will post once she can get above 3 k again

 

[Big-E]

Update - Replaced camshaft sensor and now i got another 1000 rpms out of her before hitting limiter. It will now rev to 3500/3800 rpms before limiter gets activated. Any other ideas?

At least the truck is drivable in its current condition!!


Thanks.

 

[Big-E]

Another update.. It appears the variable intake system (VIS) was sticking for some reason. I lubed that up and now she will rev up past 4k in while driving and in neutral. It still hits a "cut off around" 4200/4500 rpms (this is driving.) This really baffles me from changing the hermostat-Housing would cause all of this. Strange!!!


Big-E