[Rossco]

ok so this is the last problem with my engine conversion and it just came up today I'm so over fixing shit its not funny. (rant over)

the engine seems to be missing. when it idle it looks and feels like its unbalanced. ie. lots of moment rocking the car. when you put your hand in front of the exhaust it is coming out very hard and sort of thumping instead of running. there are pulses of fumes coming out instead of a steady stream. also when accelerating say in third in low revs it will bog down and sputter from the exhaust and then catch. accelerating is fine but it will miss when my foot is on the accelerator driving with less than 2000 revs. now the tricky bit is that its intermittent. it was all the time but I found an injector wasn't plugged in properly. I thought this would have fixed it but it has come back. it will idle fine for a bit and then start thumping again.

I have checked the other injectors
vacuum lines
leaks in the intake
cleaned the throttle body
checked for fuel leaks
adjusted the idle up slightly

anything I'm missing? cheers guys

[reeceh]

Make sure the throttle body coolant lines aren't blocked. I have a 94 1.6 in my Sierra, my coolant lines that go through the throttle body were very blocked. Also my iac valve was buggered.

[Rossco]

I'll give it a look in the morning. this seriously came out of no where today after running perfectly for two weeks. took it for a drive in the morning and everything was fine. then took it out in the afternoon and this started.

[alien]

checked the spark plugs??? mine did similar after i gave my engine a wash, took over 24hrs to dry out and return to normal.

[Rossco]

spark plugs are fine that was the first thing I though of because I had been working around them. just took it for a 30 min drive. once the engine warmed up there was hardly any hesitation through the gears but the idle was still rooted. coming up to the lights if would be fine at 1000 rpm for a second and then just drop to 400-600 and thump away.

[Rossco]

coolant lines are clear and I pulled the iac valve off and cleaned it. I don't know what to look for to see if its rooted but there was visually nothing that would suggest it

[BlueSuzy]

if its dropping a cylinder find out which one.

Id look at timing. Plug gap. Change injector

[stocker]

How old was the engine out of the conversion...

is it due for a new set of Leads, perhaps a Coil, Rotor Button, Dizzy Cap?

Start with the simple shit, that people tend to over look

[Rossco]

fuck me I just fixed it. the number two spark lead was arcing out on the ignitior bracket. it was fine before with the smaller stock mounts the lead was under the ignitor mount but the vl mount raised the engine enough so the lead was touching the ignitor bracket causing a misfire in the second cylinder.

so easy but took two days to find..
cheers for the help guys