I have had a mate look at it, who is no mechanic, but works on his own car, works as a panel beater, hangs with car people, etc. I understand that words do not translate well so I'm going to be as thorough as possible. Hopefully you're interested enough to hear me out.

First a little background...

93 TR Wagon Executive (4cyl EFI)

This car was supposed to be in excellent condition - full logbook and everything. Unfortunately soon after buying I realised the mechanic had been taking this couple who owned it it's whole life for a ride for a loong looong time. The coolant system was rusted out. corrosion ate through the timing cover soon after - and as for all the timing internals .. I'd never seen solid steel broken into jagged pieces! (the chain rail/guide thing). Although the timing internals are only a few years old they have already taken significant damage thanks to a mechanic not properly fitting my oil filter before a 30,000k road trip. thats when i decided im never paying a mechanic again without first knowing whats going on.

Now it still has a few oddities about cooling - the temp will spike to about 75-90% on the guage (not red though, no boiled coolant) for anywhere up to 40 seconds, but then drop back to normal.
Another issue is sometimes the battery light will come on, just for a second or two, then go off. and I have a recond alternator with new brushes.
Despite the problems, i can always rely on the magna to start. usually on the first turnover. it's been very nice in this way.

ANYHOW.. The main issue::eek2:

In the beginning: I would turn the car on, and it would feel 'off balance' - like how a mobile phone vibrator works, a weight attached to a motor that is not evenly distributed around the driveshaft, so it shakes. It remained regardless of which gear I was in. It would do this for a few seconds, sometimes id have to kick the revs up to 2-3k to 'clear' it, but it would go quickly, and id be on my way as per normal. It's a very 'regular' wobble. it sounds kinda like when a motorbike idles 'put put put put'

THEN one time... it just didn't go away. It took about 5 minutes of warming up. I put it in drive and veerry gently went around some backstreets for a while. I should note this was one of the first cold nights this happened. Maybe not related. though.

Now since then, it's taken me warming the car up for at least 5 minutes.

My feeling at the moment is that 1 or possibly 2 cylinders are not firing?. I'm definitely down on power and it makes sense why the 'put put' and the off-balance thing. The ignition leads are all new - gave them a fiddle to no effect, theres nothing wrong with the distributor cap. Havent checked plugs yet as i need the tool. The weird thing is it is both repetitive, but also sporadic. I'll get to that.

There are some interesting oddities I'll point out now...

While it's cold and 'wobbly' - As it warms up, the lower gears stop being wobbly before the higher ones. eg it reaches a point where I can drive fine in L, but if i go to 2 or D it will return to wobbling. Eventually all becoming fine.

While it's warming up/still a bit cool - I can hit a 'sweet spot' in the RPMs.. it varies, but generally around 2000-2500
If I can hold the car at the exact right rpm I feel it surging in power - kinda half the time it is shit and half the time it is back at full power, but very sporadic short bursts, like fraction of a second between the change.
I will also get this 'surge' effect just at the point where the car is about to stop doing its vibrating putput act and start driving normally.

This initially made me think fuel filter, but the more repetitive wobbles dont make sense for that as all cylinders would be just as fuel starved as each other, wouldnt they? I actually bought a new filter but I can't get the old one off anyway even if it did have something to do with it. Also it's always the same kind of vibration.. so I presume it is the same cylinder/2 that are having problems, rather than just any random 1-2 out of the 4.

Once the wobbles go away, there are still occasional 'skipped beats' When idling at the lights, I hear it dropping just a fraction of a second, but quite frequently, say 2-4 times per second therell be a tiny drop. never enough to stall the car though.

There was also a case where driving it up a steep hill made the problem re-appear, and i had to drop back to 2nd to get it to stop wobbling again.


OK I hope you made it through all of that... I hope I was clear enough! If you have any ideas please feel free to share them, however sure you are!


ONe other thing I will mention - don't know if this is a sign it's related or not...

I notice sometimes when driving along perfectly fine, there is a very small surge in the amount of power the car has - and more noticeably to my body - the air conditioning becomes colder and the fan strength increases, ever so slightly. Could this be a sign of some electrical issue? or would this just be due to something in the engine switching on/off affecting the entire circuit. (like swithing an electric jug on causing an oven fan to slow down a little bit like what happens in my kitchen)

Battery light coming on intemittently could be a sign of alternator problems but also check your connections are sound on the battery as well as the earth connections on the body and motor for the negative cables.
Do a compression check to see if you have one cylinder down on pressure that may be causing your uneven running.
If compression ok check fuel pressure and distributor and spark quality.Injectors may be at fault possibly also.
Timing cover corroding thru is a common problem if the coolant is not kept up to scratch. Vee

So much to read.
Temp spike may be a faulty thermostat. Vee

Thanks for the thoughts...

I went for a drive last night and I picked up on a little more... I'm still getting a feeling it is a fuel issue - I notice that when its at the point of changing over from cold to warm (and becoming 'ok' to drive) - if I ease right back off the accelerator I can get it to settle down sometimes - eg if i take off from a set of lights at the normal rate and the problem appears, I can get it to smooth out to normal by easing right back on the accelerator.

Weak spark. Look for damaged contacts inside the distributor cap, or cracks, arcing leads (check at night), dud spark plugs, corroded connection on the wiring at the distributor.
If nothing suspicious turns up, change the coil and power transistor. When these act up, they can be good cold but go weak when hot.

I had a simular issue with the engine running rough and surging. Dizzy cap and rotor fixed it. AS per above post check dizzzy cap for cracks / bad contacts.

Temp. spikes like that, coupled with a cylinder not firing, are signs of a worn out (possibly blown) head gasket leaking coolant into a cylinder. That would definately take out any cylinder it leaked into. And with coolant going directly into a cylinder, it will heat up. Thus causing temperature spikes.

You should take the radiator cap off when the engine is cold, then idle it for only a few minutes. Look for any signs of bubbles coming out.

The fan getting stronger is a sign of a faulty alternator giving too much power. The intermittent battery light is also a vital clue. This extra power can slowly kill electronics.