When i start my 1998 honda , the idle rmp goes up and down btw 2 and 1. then when i put it in park it shuts off. i changed the spark plugs and the car started better. but right now it cant hold its rmp idle

sure, rolling in gear you mean. (same effect as push starting a car with M/T) what speed did it restart, 5mph or 50 or 85mph.?)
what transmission. A/T or M/T? BEG ERROR there !

shut down,?
you mean stalls,
and engine can do 3 things
run too slow (way below 800RPM idle , illegal idle speeds)
stalls (rpm goes to zero or you find zero power from the engine )
if you stop the car, and the engine stalls that is an engine stall.

or run perfectly.

does your model have a tachometer to you can see RPM?
and if idle controls work,
not posting the trans type, (non body does here) makes answers near impossible. infact most will just ignore you posts.

with a M?T car the engine immediately returns (hot ) to 800rpm
and is regulated very closely by the EFI brain (PCM)
if not you are seeing IDLE control failure.
with and A/T there is no MT clutch and when you stop
the autoclutch drags (wastes fuel like mad) and puts a huge load
on the engine, stopped say at a red light. the idle controls
on A/t are greatly taxed here.
so RPM can drop real low. fail. or stall. below 800
a stall happens at about 400 RPM.
the M/T can at any time be restarted on the fly (moving)
but just dumping the clutch. or just waiting as you coast in gear.
this is how push starting any M/T car works.
but on an A/T car , on the fly restarts take huge speeds.
and only works on A/T that have 2 oil pumps.
the A/T with no rear pump , the A/T can not be push starter
or coast restarted, if the front pump is dead(engine stalled)
im not looking up your tranny spec. because you never stated, it.


my engine stalls. (not tranny slip)
1: bad 12vdc power to any EFI system component.
2: never ever tuned up per the free operators guide in glove box.
3: lost engine compression. 1 or all cylinders.
4: lost spark. (or timed wrong, early cars have distributors)
5: bad fueling. too much or too little

when the engine runs , does the MIL, CEL glow running
btw the CEL also glows, at all stalls. the lamp only means.
I HAVE ELECT power, now.... only.

your idle could be set a little low, mine did that once. also you could be low on trans fluid or the trans brain and/or solenoid/s going bad.

It sounds like your Fuel Pump is failing once it get warm.

have you put a new set of plug wires on it. use a spark plug tester, and put it between plug wire and dist, cap. if it is sparking you will see it. if yes and not to plugs put on new plug wires. good-day ! if above checks out. remove dist, cap and see if shaft of dist, is turning. some of the hondas have a plastic type drive gear on bottom of dist, shaft. that goes bad.

Sounds like it may be the spark plugs. If you have a spark maybe a fuel filter is clogged? Hope all goes well!

• Sound a little like block exhaust or exhaust system starting to fail. If not this, the spark plugs are suspected. Have an old set of plugs around that you can replace to find out. Good luck.

check for a loose harmonic balancer(big pulley on bottom of engine.

oil soak can damage this part too.

Make sure all spark plugs are sparking.You cant tell if you have a faulty one by looking.

MAKE SURE WHEN YOU PLUGGED THE SPARK PLUGS IN THAT YOU GOT THEM IN THE RIGHT FIREING ORDER,ALSO MAKE SURE THAT YOUR THROTTLE BODY IS OPERATING NORMALY WATCH IT WHILE THE CAR IS RUNNING TRY MOVING THE THROTTLE BODY ROD BY HAND

ck the coolant level if this is ok then its the idle air control valve