24sc400

Alright, Newbie here!

purchased a 1994 sc400 knowing it needed a bit of work- I have records of previous maintenance, Spark plugs, oil change, Caps, Spark wires etc.
and the good o'l MAF sensor, troubles started a couple years back apparently, rough idle, seems to misfire and rpms may/may not drop/go up when idling, hesitation when accelerating but has a sweet spot around 2000-2500 rpm where it drives better-ish but hesitation still slightly noticeable. Hesitation/jerking is less in 2nd and L, exactly the same with Maf unplugged.

previous owner brought it in- diagnosed with a bad MAF, replaced- 2 times. apparently the Replacements didn't work as well compared to the one that is currently on the vehicle, i don't see any damage around the housing, i use compressed air to blow off the maf, but nada...

Any ideas ? I'm honestly stumped!

i checked for Vac leaks, TPS seems to be fine, coolant fine, oil fine, Trans oil fine, heat works good, ac fine, New Alternator, ECU looks good, i dont see any broken/oozing capacitors or anything for that matter.


Maybe I am missing something simple ? Thanks in advance

Tallyhoe

If its misfiring I would check the ignitors on both sides. My ignitor was cracked, and would just shut off at any given moment, if I didn't give it gas. One evening it just went, and cooked both my cats, I've posted pictures on my build thread. Now, I'm not sure how I resolved the hesitation and rough idle, but I think it was the radiator, or air in the cooling system. It wasn't indicating anything at first, but over time and use I could see small traces of coolant started forming on the lower splash guard. Once I removed the splash guards, I started seeing puddles on the ground, additionally the full coolant facials the engine was receiving led me to discover I had a crack on the top driver side corner of the radiator. If the coolant was below the full line in the reservoir, it would swing the idle up and down, once I filled it up to full on the reservoir, it would usually settle down, this also aided in the jerking. I got my ECU rebuilt and most of the symptoms came back for a couple of days but went away soon after.

t2d2

iTrader: (8)

Ignition coils cause hesitation problems on these cars, although it's usually at specific RPMs (1500-ish, as I recall), not across a range of situations like that.