Engine stumbling badly under load
#1
Engine stumbling badly under load
Hi,
I am stumped with a problem with my engine - its a 1998 subaru impreza sport - EJ20 naturally aspirated.
Whenever i put the engine under load, for example driving up a steep hill, the engine stumbles badly and nearly cuts out.
I`ve been through all the basics - fuel supply is good, changed the plugs (twice!), changed ht leads.
There are no inlet manifold vacuum leaks or exhaust leaks as far as i can see.
The engine starts and idles fine and will pull away reasonably well. When i come to change gear, especially on a hill, when i go to put my foot down, the engine stumbles as if starved by fuel.
There are no error codes displayed. I`ve checked the throttle position sensor - this gives a reading of 0.5ohms closed and 4.5ohms wide open throttle. The air speed control valve looks ok and turns fine when i`ve inspected it. I`ve also replacd the MAF sensor with a replacement which made no difference.
If anyone has any ideas or suggestions, any help is appreciated!
cheers,
mike
I am stumped with a problem with my engine - its a 1998 subaru impreza sport - EJ20 naturally aspirated.
Whenever i put the engine under load, for example driving up a steep hill, the engine stumbles badly and nearly cuts out.
I`ve been through all the basics - fuel supply is good, changed the plugs (twice!), changed ht leads.
There are no inlet manifold vacuum leaks or exhaust leaks as far as i can see.
The engine starts and idles fine and will pull away reasonably well. When i come to change gear, especially on a hill, when i go to put my foot down, the engine stumbles as if starved by fuel.
There are no error codes displayed. I`ve checked the throttle position sensor - this gives a reading of 0.5ohms closed and 4.5ohms wide open throttle. The air speed control valve looks ok and turns fine when i`ve inspected it. I`ve also replacd the MAF sensor with a replacement which made no difference.
If anyone has any ideas or suggestions, any help is appreciated!
cheers,
mike
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#4
i haven`t had an o2 monitor on it as i`ve not got the facilities to do that at the moment - i`d have to take it to a garage to get that carried out. I`m trying a few different things before i take it there as i`ll probably have to get it flatbedded to a garage - don`t want to risk knackering the engine by driving it it if its not quite right or running lean.
i m picking up a new timing belt at lunch and will check tomorrow if the current one has slipped - this is about the only thing i haven`t looked at yet.
i fitted a new fuel filter and the fuel pump seems to be working fine. no blockages that i can see anywhere at the moment.
thanks for the link - i`ll put a post up there too.
cheer,s
mike
i m picking up a new timing belt at lunch and will check tomorrow if the current one has slipped - this is about the only thing i haven`t looked at yet.
i fitted a new fuel filter and the fuel pump seems to be working fine. no blockages that i can see anywhere at the moment.
thanks for the link - i`ll put a post up there too.
cheer,s
mike
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