80 series help strange issues

[fjsigs]

Good evening, im having some issues with my 80 series that I just can't figure out. This is a 1993 80 series from Japan with the 1fz-fe and 175k miles.

The issue: Slow and lagging acceleration, bouncing rpms at idle in drive, jumping throttle when trying to accelerate at a faster speed.

parts and fixes I've already tried:
- oem rebuild MAF sensor
- air intake hose
- air filter
- oil change
- oem iac valve
- pcv ladle, grommet, and hose
- new vacuum hoses
- new fuel filter
- spark plugs, plug wires, distributor cap
- adjusted the throttle position sensor ( this helped a little bit )

no check engine light or codes at all so I'm pretty stumped.

any advice or expertise or fixes are appreciated!

 

[ppc]

Fuel pump relay, fuel pump or wiring.

 

[fjsigs]

Fuel pump relay, fuel pump or wiring.

Ill check these!

 

[MileHigh80Guy]

Good evening, im having some issues with my 80 series that I just can't figure out. This is a 1993 80 series from Japan with the 1fz-fe and 175k miles.

The issue: Slow and lagging acceleration, bouncing rpms at idle in drive, jumping throttle when trying to accelerate at a faster speed.

no check engine light or codes at all so I'm pretty stumped.

any advice or expertise or fixes are appreciated!

I chased an issue for awhile before I found out my CEL bulb was missing, yours could be burnt out too, but the simple test is the "key on" dash lights.

The CEL should illuminate with the others on the dash before you crank it over, if you don't see it, you'll need it for proper troubleshooting.

Once I found mine was missing, I had 3 codes (O2, KS1, KS2). Hope you don't, but take 3 seconds to check. Good luck.

Worth a simple check, then move on to some of these:

Broken spark, (cracked dist cap, broken wires, damaged plugs), a compression check and an intake smoke test may also help.

Also, on my OBD1 CEL/wiring "journey" I found plenty of snapped connectors and harnesses that were exposed and almost completely broken wires. There's a multimeter test for resistance in the 94 EWD FSM for most sensors that will go over the test and the ohms and voltage expected ranges the ECU wants. Good luck.

 

[mrsleeve]

Vac leak from a failing or faulty brake booster?