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95 Tercel shutters at idle?

I have a 95 Tercel that is my daily driver. At 100k miles, I had to rebuild the engine (long story) so my sons and I pulled it and put it back in. I’m very picky, so I made sure everything was clean and clearances were right, etc. I cleaned out the intake and throttle body, new belts, plugs, etc.

All seemed well as it started right up and drives great. But when you have it in Drive at a stop sign/light, the car vibrates quite a bit. You step on the gas to go and it seems to be fine (though while cruising a long I can feel the slightest little hiccup every once in a while). I have replaced both coil packs, spark plugs and wires with no change. I replaced the fuel filter and have made sure everything is in place (no vacuum hoses loose, no wires disconnected, etc).

I can’t figure out what is going on and I’m about to go nuts. I haven’t replaced any sensors or injectors, but as they aren’t cheap, I don’t want to start just randomly replacing things.

The car is going to be my 16 yrs olds and I just want to resolve this so I know it isn’t something that is going to leave him stranded some day.

Any help diagnosing and tracking this down would be VERY much appreciated.

In drive, the vibration while you are stopped could be a damaged u-joint. It is actually pretty likely, since the u-joint is meant to fail under stress. Replace it for about fifty dollars.

Thanks for the reply. What u-joint are you referring to? Having pulled the engine and transmission out, I’m not aware of any u-joints but it could certainly be there.

I replaced the rear engine mount and think I need to replace the front/side and the transmission one, but again, don’t want to just start replacing stuff randomly.

The slight stumble (and I mean very slight, but I am sensitive to cars that way) when driving makes me think it is in the fuel system or spark, or maybe a sensor, but just not sure. Both O2 sensors have been replaced, so I don’t think that is it.

The car has no u-joints. It has only CV joints on the front half shafts.

Unfortunately these minor & intermittent problems can just be really hard to track down. Is it safe to assume that the check engine light doesn’t come on?

When it is vibrating at idle are you thinking that it is misfiring? Or might one or more of the mounts be broken or deteriorated? If you just pop the hood & watch is there a lot of engine vibration?

Have you checked the fuel pressure? If it is borderline that could give rough idle and the occasional hiccup while driving.

I’d also check to make sure that the intake manifold isn’t leaking. You can use a propane torch w/ a hose rigged up to run propane around the intake while it idles. Or you can spray something like carb cleaner around the seams. If you hit any spots that are leaking the idle should respond.

There are a couple of things that could give an intermittent vacuum leak. One would be a sticky EGR valve & another a sticky evaporation purge valve. There are times that they are supposed to open but if they got hung up once in a while the computer wouldn’t be adjusting the fuel mix. Those are a long shot, but what they heck. For diagnostic purposes each of those things could be capped off to see whether it makes any difference.

Let us know how it goes.

Yes, VERY hard to track down. Has me about banging my head against the wall. Even on this older basic car!

No on the check engine light.

On the engine mounts, when you put it in drive, I can watch the engine shift noticeably and then when you put it back in drive, it shifts back. I thought this was the rear engine mount so I replaced that one and it didn’t seem to make any difference in the shifting or the rough idle. I can replace the other two (passenger side and transmission) as the car is 15+ yrs old and 120k miles if there is a chance that would do it. But that doesn’t seem linked because the idle in Park as started getting a little rougher now. But maybe that is even more of an indication they need to be replaced.

Haven’t checked the fuel pressure. What’s the easiest way to do that, some sort of inline gauge? Did change the fuel filter but that was about in there. When I rebuild the engine, I didn’t do much with the injectors other than a cursory inspection and replaced the seals. Gas mileage seems to be going down a little. Think I was up about 33 or so on the highway, now about 31ish, but could be the driving more than the car itself.

Haven’t really looked for vacuum leaks, but that is something I should do.

I’ve got a 95 tercel DX as well, and i’m having some of the same problems. I don’t know much about cars and what I do know is what I’ve learned trying to get mine fixed. About a year ago I had some burnt valves and so i took the head off and took it to a machinist, and when I got it back it ran a little choppy. I replaced the egr valve and the O2 sensor and for a while it was running pretty well. Now it is doing the same thing again. I lose power while idling, at times it seems like it’s about to die. There is little power when I accelerate from a dead stop. At higher speeds it seems to run better. I think it may be worn out piston rings. A few days ago i replaced the spark plugs. The old ones were about a year old, pretty expensive ones, i forget the brand but they were the iridium ones. Although they were only a year old they had a BUNCH of corrosion on them. I don’t know if the problems you had are the same as mine or not, but I’m a little curious why you had to rebuild the engine to see if we have some of the same problems. If anyone has any ideas, I’d like to know. Some of the possibilities i heard is that it could be a bad computer, bad fuel pump, or bad rings.

I had to rebuild the engine on this car because one of the nuts holding the piston rod to the crankshaft came loose. It didn’t come off, but loose enough that the rod and piston were slapping around. I replaced the crank, the one rod, put in new rings on all pistons, honed the cylinders, new bearings, had the head cleaned and new valve seals put in, new head gasket, cleaned out the EGR, cleaned out the intake. I didn’t have the head machined and I honed the cylinders by hand (VERY carefully). I replaced both O2 sensors along the way as well.

The engine holds compression, doesn’t seem to burn a drop of oil. Coolant is clean and staying at a constant level. The only thing that did happen is one of the teeth on the back timing belt pulley on the crank (teeth used with crank position sensor) broke off so I had to weld it back up and grind it to be exactly like it was before. I have pictures and it is the exact same gap and height, etc. so I don’t think that could be it.

Lately the shuttering at a stop light has gotten a little worse. Putting it in Neutral or Park at the light helps but you can definitely feel it where you could barely tell before. When I rebuilt the engine I put new plugs in. At this point, the engine has about 10k miles on it.

At this point, frustrated and wondering if it is worth it, I have these on my list of things to check:

1 - Motor Mount. I replaced the rear but the passenger side one isn’t great and I can see the engine move considerably when you put it in drive. Maybe the transmission one too. They are factory and at a 118k miles, they probably should be replaced anyway. Just not sure if that is the cause. Cost is about $50 for each mount (NAPA)

2 - Vacuum leak. I’ve done a cursory visual inspection and nothing seems out of whack. Need to check using other methods (some mentioned here).

3 - EGR Valve. It’s original, and although I have cleaned it, I guess it could be causing issues. Cost is about $210 (NAPA)

4 - Sensors. Throttle position, crank position, other? I’d prefer to test these some how instead of just randomly replacing as they aren’t cheap. Crankshaft - $70; Camshaft - $60; Knock - $160; FI Temp - $20; MAP - $300; Throttle Position - $95.

5 - Fuel injectors. Grasping at straws but it could be the issue or part of the issue I guess. $159 each.

I have done so much to this car at this point, and with a rebuilt engine that only has 10k on it, I don’t want to give up on it. But it’s getting to be a pain.

Are there easy ways to test the items above? Are there other things that might be causing this problem?