ok so heres the deal. i bought a 1989 240sx 5speed coupe with 118 000km. i bought it off a guy on a farm. he says it has been sitting for a long time. it starts fine and all is great but i have a weird idle. it will be sitting at 1500rpm then it will jump to around 2000rpm then drop back to around 1500rpm and it repeats every like 5 sec. could this be a bad idle air control valve or is it just because it has been sitting for so long and needs a tune up?
Well it needs a tune up either way, so do that first.
Could be a vacuum leak also.
Check the vac lines for cracks ect.
ok thanks. some of the hoses did look like they were starting to crack. ill check that out.
If the car sat for “X” amount of years. Trace everything. Every hose, wire…everything. Let it run and get nice and hot. Oil change, then another. FULL tune-up. FRESH gas is a major factor as well. Then diagnose electrical engine components. Do the basics first.
Coolant bubble.
- 1 for the coolant , take the cap off , let it run, bleed it and make sure its full.
still rec tune up, fresh gas
search other recent threads for tune-ups and how to solve the idle issue.
ok so i pulled off the iacv and cleaned it with air intake cleaner and put it back on. replaced a couple of the bad vacuum lines and my idle is still fluctuating.
im thinking it is a bad iacv since my mechanic said that the tune up only makes it run better and doesnt do anything with the idle
a tune up has a lot to do with your idle. it just won’t seem like it if you have an over riding condition.
is she hunting or just idling high?
when i start her up its sittin at about 1500rpm creeps up to close to 2000rpm then cuts off and drops to 1500 again. and it keeps repeating that. so i think i need a new iacv. all the vacuum lines are good. i replaced a couple that were staring to get bad.