Misfire 1 to 3.5k, gone flat

[ETERNITY]

There is a misfire from 1-3.5 revs k and it's lost power between that rev range

It was running very well prior to my mechanic taking it away to fix a radiator hose leak, oil leak and it has come back with this misfire. He mentioned that he checked the spark plugs and I have checked all leads and there all connected.

The only visible thing that I can see is that the air flow meter lid is missing, which I am going to replace and was missing prior to the mechanics.

Any advice on what I should check or do

[sweep]

Leads on in the correct order?

[German-Whips]

What engine is this?

[ETERNITY]

2.5 m20

[ETERNITY]

Leads on in the correct order?

Just checked and all in correct order.

Thanks sweep

[sweep]

which hose was leaking?

[ETERNITY]

The first thick one that you can see if you look from drivers side

It's so annoying to drive and feels flat.

[ETERNITY]

I can see water around the air flow meter, as there was no cover on it and there is coolant all around the engine bay from the burst hose.

It feels like it's running out of petrol and is smelling rich

New air flow Meter?

[sweep]

Any pictures?

[ETERNITY]

Will update with pics tmoz.

[Brianmoooore]

Post facelift M20? If there's work been done in the engine bay, then the plug and socket for the injector loom and coolant temp. sensors, under the inlet manifold is a likely suspect.
Check the resistance of the 'blue' temp sensor AT THE ECU PLUG, with the engine stone cold, and then at full running temp. Don't touch the plug and socket until you've done this.

[ETERNITY]

Post facelift. Will do that Brian and report back

[ETERNITY]

Ok checked spark plugs and blue temp sensor , and they are all good

The hose they replaced was near the distributor, so my guess is that they must have damaged the dizzy and this has caused misfire

Any clarification?

[ETERNITY]

Ok update

The mechanic wreckons it was the spark plugs and he changed them without my consent and now wants £45.
The same plugs were in before the misfire and it ran A1. He probably dried up the dizzy because they must have put water In there while changing the hose.

[sweep]

So it was the plugs?

[ETERNITY]

No because why wasn't the spark plugs causing a misfire prior to him fixing the hose, it don't make sense

1 hour after the hose is fixed I get faulty spark plugs

[Brianmoooore]

They might not have been causing a misfire, but they might have been completely worn out, and a bit of water around the distributor might have been enough to cause a misfire that wouldn't have occurred with good plugs.
How many '000s of miles had the original plugs been in the engine for?

[ETERNITY]

About 3k max. When I checked the spark plugs before I sent the car back to the mechanic to sort this misfire they looked worn out and I was going to change them myself.

[ETERNITY]

Misfire now gone and spark plugs changed but now car is idling rough and revs are hunting.

He said he used 3 point spark plugs ngk, unsure of model no. I usually use ngk bpr6es

[Brianmoooore]

This is what happens when you don't do your own mechanical work, and let someone else loose on your car!
M20s don't like multi electrode spark plugs, so they should be changed back to the correct ones, but I doubt if this is the cause of your rough idle and hunting. These are symptoms of a weak mixture, so have a good search for air leaks on the intake side.
You say your plugs were only 3k miles old and were worn? They should last far longer than that - at 3k they should be indistinguishable from new, except for colour.

[ETERNITY]

Ok I checked for air leaks and found none.
I have just took it out and it seems to be have cleared the hunting revs and bad idle.

Probably Ecu getting confused

"The joys of owning a E30"

[German-Whips]

Ok I checked for air leaks and found none.
I have just took it out and it seems to be have cleared the hunting revs and bad idle.

Probably Ecu getting confused

"The joys of owning a E30"

What did you do to it before taking it out?

Did you happen to disconnect the battery for an hour of more and then reconnect it, fire the car up and let it idle for 10mins?

That is supposed to reset the idle settings for the ECU.

[ETERNITY]

I did nothing, just looked around for air leaks and then took it out and drove it hard. It seems fine and is running great with improved power and seems to pull better than before.

[German-Whips]

Maybe it needed a good beating and a thrashing!

Did it seem it fix itself before you took it for a drive, or was the problem when when you started the drive, and then seemed fixed towards the end of the drive?

[ETERNITY]

It was hunting and idling rough, shaking and at the end of the drive it seem settled and now it feels responsive and clean acceleration.

I don't know what's sparks he has used and whether I should let the car run with these in.

[pianist]

I wouldn't use three or four electrode sparks, go back to original stuff before you damaged something in your ignition system. It seems too me that something that was wet had dried it self out and now is back to normal, you mentioned that AFM cover was missing which might be the cause, just make sure it is sealed in the future so it doesn't get wet and dirty again

[RobWill116]

Get some NGK BPR6ES plugs back in, when I brought my e30 it had some bosch three electrode sparks - first thing i did was change them.

[ETERNITY]

I just paid £45 to have these fitted and it's running fine, I am thinking of running these until my next service in 3/4 months.

If it is going to damage the ignition system then I will change, so unsure what to do.

[Brianmoooore]

You paid £45 to have plugs fitted that are suitable for your car. This is what you are entitled to have, but not what you have received.
Instruct your mechanic to fit plugs that are suitable for the car, at no cost to yourself.