'98 Tacoma Speedo Jumping and RPMs Surging, Please Help

Hey there Taco dudes! I did search the forum before posting here, but not much is coming up. This morning my speedo was jumping quite dramatically and it sounded like my RPMs were jumping in sync with the speedo, but I dont have a tach to confirm. I could hear the engine revving as if I was giving it gas/ going faster, but I wasn't. This problem just started this morning right after leaving the house. I drove it like that for maybe two miles before turning around and swapping vehicles. Anyone have any ideas for me to check when I get home this evening?

Vehicle specs:
1998 Tacoma w/ 214k miles. All original.
Base model 4cyl, auto trans.

Thanks for any assistance yall can provide!
-Jake

 

Probably start with the throttle position sensor, or crank position sensor. Look for the Factory Service Manual sticky thread at the top of the 1st gen forums and find yourself a PDF of the FSM. It has troubleshooting steps for those components.

 

Bump.

Anyone have any more ideas?

 

Obd2 codes?

 

I got the ol girl going again this weekend, so I wanted to follow up my post for any future internet sleuths.
I couldn't get my OBD2 scanner to read, I kept getting a "link error" when I tried to use it (connected fine to the wife's minivan), so I took a shot in the dark and replaced the throttle position sensor. That didnt work, so I got a different scanner from my buddy. That one connected fine and gave me a read out. There was a background code (it was greyed out) call out of P1335 which lead me to the crank position sensor. After replacing that, she's running fine again. I had to drop the alternator and the alternator holding/tensioning bracket to access the CPS. It would have been easier if I had pulled off some of the radiator hoses, but I didnt have any fluid and didnt want to mess with that. Thanks for the input, dudes!

 

Forgot to mention that I took my multimeter to both of the CPSes. Of the three pins, only one set would give a reading. The other combinations just came back open. The bad CPS gave me a reading of 2.2ish Ohms and the good one was right at 2 Ohms. Maybe that will help someone troubleshooting in the future.