Hey guys,

I have a pristine 91 Cressida, that is - it is pristine considering it has done 270,000 clicks!

It is clean, straight and the motor has lots of power and runs pretty clean.

But after I bought it, about 2-3 weeks, it started to grumble, it started with a small miss, then progressed into what feels like the loss of a cylinder - or even two! For usually short and VERY random periods.

Back then it mysteriously disappeared. So I thought it was nothing, a bit of crap in the fuel?

But then one day a week after it first did it, it started doing it again, and was being a **** and would not start, it then would go away, and I found it may not return for 10minutes, 10 seconds or 10 days. once it is doing it it seems to stay until it is switched off.

It MAY be there when you start again, but it is definitely a reaction to something internal, it has been seen to dissipate when driving. I reckon it is occurring between 20% of the time I use it, but much more lately.

Lately it is VERY regular, almost every time it runs. It is very hard to start if it is doing it, whereas when it is not doing it and always before it ever did it, it kicks over and purs like a beast first time everytime, with no issue.

When it is doing it, revving the motor,, (or pumping the throttle lever) sounds off a click in behind the dash, in some switch, but not every pump of the throttle does it, so something in behind the dash is reacting to what I am doing with the throttle as it senses the disorder. Also, when it does click during what is essentially a massive flatspot, and fails to run smooth, it stops clicking and seems to cut the motor, then you can repeat, then you have to come off, and try again etc. (typical symptom of misfiring, yet this is occuring with the old AND the new sparkplugs, so it is not plugs)

If it keeps revving up, it revs hard and 'sounds' fine, but really at hi revs it is still running on less than the full 6 cylinders, that is obvious, the symptoms are typical, the cause is the mystery, and so is the role or importance of that clicking switching in behind the dash - I will try to post a video.

Sometimes it will not idle, and it will stall, that is why I here the click, trying to keep it running at rest, (when it is like this when driving it will stall under brakes - it is an Auto) and yet sometimes it will idle at 1500-2000 to keep itself running, (airflow meter?) and will be hard to put in gear or need more pressure to pull up and keep idling - so it goes either way - idles badly, low and rough - resulting in a stall, hard to rev up, OR it idles high but with some power and ability to rev, but with lots of smoke and exhaust.

When it is doing it it is like a typical hesitation seen in a carburetter car, and can mean danger in traffic and at intersections.

The initial suspicion I had was simply rotor button and distributor cap, so I replaced and it seemed to go away, problem solved, - ****, it was not!

Then I got new leads, and new plugs, cause the old plugs looked like they had been shorting outside, around the tubes, (after the pooling of some oil in the top - yes cleaned it all - motor is very clean), but no dice, still doing it. The mechanic was sure that would fix it after what I described. I got Top Gun leads.

The water is clean, temp always correct and stable, the oil is clean, the motor sounds and looks to be running great, there is definately no gasket issues or mechanical faults.

My mecahnic who came and looked at it, when he did my oil and plugs said that, (of course it failed to do the problem when he was there - a TRUE gremlin!) if the new plugs and leads don't fix it then when I run a tank with Nulon injector cleaner it should clear up, he said the injectors seemed fine, but I am halfway through a tank of good fuel with the injector cleaner and it is no better, if not worse.

I am sure it is an electrical issue, but I cannot imagine what could be doing it?! Coil?

He checked the computer, it said no issue, no limping or any message of problems, when it does this, no engine light, no nothing, the motor seems to just be firing on 4-5 cylinders, and of course it blows a bit of black and fuel laced smoke.

Other issues:
Once I got in, tuned the key and found nothing, - except a small very short movement by the starter motor, then no power, not even clocks or lights, - I thought it was a blown fuse, but nothing, fuses were fine, - then I tried again, nothing. So I looked again, then got back it and it had power, I thought I would get stuck and ran off the ring the wife, then came back, and this time the starter motor made the slightest move again, (millisecond) and everything shut off again.

I thought it must be the battery, it must have died, so I twisted the battery terminals on tighter, and it seemed to fix it, never done it since, a one time issue. Strange.

One other thing is that the intake manifold tube, the rubber bending one (running from airbox to the straight plastic tube over the cams) is perished in one spot, but seemingly well sealed with tape.

Other than that, there is one missing vacuum tube on the back (near firewall) of the intake manifold, that I plugged up, no lose tubes or any evidence of something not linked to it or missing. I put some plastic on it not long after I got the car, does not seem to be related - but who knows.

There is a plug on one vacuum tube on the front of the intake manifold, with another next to it that looks like it is for the cruise control, it runs to a vacuum solenoid near the injectors, (will submit photos tomorrow), and these two might be on the wrong ones?

The cruise control is a little suspect - cause when I try using cruise control it goes into CC, but then usually it quickly cuts off, (tries to switch back the gearbox to a lower gear when and if it stays on at all) and then the Cruise Control light flashes 5 times, once it switches itself off.

Thanks for any tips guys, I am hoping someone else has experienced this and can help with where to start, it can be expensive replacing all the bits to find it might have been a 30cent part!

Sorry for the long post.

Cheers,
Sean.

Thanks for all the good info.

First off, the "Other Issue" with the bad starting, is a bad battery connection. Simple fix is to clean the wires.

You other main issue sounds a lot like a fuel pump to me. With that many miles, I bet it's near warn out and has issues keeping the fuel pressure up at time.

I am unsure on a Cressida, but most Toyota have test points to check for this. The quick and dirty test is when it dies, crack open the fuel line. Normally the banjo bolt to the cold start injector is the easy place to get access. If fuel squirts out and gets in your eye, your buddies eye, then you have about 30psi of pressure and the pump should be good. If it just drips out and catches fire on the hot exhaust, then your fuel pump is bad.

The correct way is to connect up a fuel pressure gauge to this point and watch the readings. Most Toyota's have a diag port near the fuse block under the hood that will allowed you to jump two pins with a paper clip and run the fuel pump with the engine off.

Once again, I don't have your car, but some have a vacuum fuel pressure regulator. It uses vacuum to regulate the fuel pressure by bleeding off extra fuel back into the tank. I have never seen one fail, but I would look into it with your missing vacuum line problem.

The other thing could be electrical. The coil could be just on the edge of dieing. Connecting up an extra spark plug and checking for a nice hot "blue" spark when it is having problems running would be a good test.

Hey, thanks LotOMiles for your reply,



I recall my mechanic cleaned the terminals, and that has never erupted again.



LOL, that is one way of testing, I think you are onto something.

What is funny, is I was going to post images of the vacuum hoses, but I have been away from dawn to dusk and it is too dark for me to do that today, so tomorrow I will try, but I called my mechanic today, after getting a bad vibe from an Auto Electrician I called, and thought he might want to come see it now that it is so much more consistent.

I really have been thinking this is electrical, but how about that, - great minds think alike - he also said it might be the fuel pump, so I think you and him are on the money - at least I hope, a fuel pump means less hassle compared to an electrical fault. He is going to put a guage on it tomorrow.

I will also get him to look at the coil, thanks again mate, I will keep you posted.

Regards,
Sean.

Well,

It looks like I got dramas, the mechanic came and tried a pressure gauge and found no issue with the fuel pump.

And what is worse, the D A M N thing put on a lovely show, other than running a bit richer, (it was blowing some black but that is the most minor example of what it has been doing and is not easitly noticed) it hardly skipped a beat!!!!

When I left him with it he said it conked out twice and yet it wasn't doing what I claim it has been doing which is running rough and being a bugger, he thought the injectors were getting put into full open when he saw it conk out, and yet he could not get it to repeat to test them, and it never played up other than that.

He took it for a drive waited a long while - 5mins, and no dice, he said he may have fixed it from what ever he did, which was simply connecting the guage, and playing around!'

So when I get home I assume it should be fine, I try to start it and it is doing it just as bad, IF NOT WORSE than ever!!!!

It was wanting to stall, it was rough, it was being cranky, then it would not start, it got so flooded it would not start.

WTF

Any ideas people?, this is PAINFUL.

Sean.

Problem Solved.

It seems that even though the flexible intake air tube was suspect, I replaced that after it broke when looking for an after market solution, the real problem was the air flow meter, even though those hoses play up, no one can be sure how much damage is done to the meter due to the sucking of additional air, that was never my problem, it remained well sealed all the while I had it, but that is a common site on this model.

I got a second hand one from a wrecker in good condition and also got a great very new condition tube, (will post a photo) and the car is going perfect.

It seems they rarely play up, and hence why the problems were so unusual.

Thanks for your help LotOMiles.

Sean.

I also solved my Cruise Control, it seems the vacuum hose was attached to a small OUTLET tube under the intake manifold, and the vacuum tube I plugged was where the tube should have went, problem solved! (will also post a photo.

Thanks for the reply. That is the first time I have seen that problem caused by a bad intake hose.
Glad you got it fixed.

Hey,

Yer, just to clarify, that is speculation on my part that the broken hose or a split could lead to putting the airflow meter out of whack or damaging it's sensitivity etc. But no doubt a possibility.

The real issue was the meter, my mechanic said they rarely play up and that is why he said I should get a way with a second hand one.

It is running really well, and no doubt will get me out of trouble until I look at an aftermarket system.

Sean.