Driveability issue

[hawg keeper]

Hello friends, my trusted 93Festiva is sick for the first time. What it does is stumbles and bucks when pulling away from a stop or when turning a corner and its in 1st or 2nd gear.You can control it by gentle use of the gas. The problem is INTERMITENT. It will act up when either hot or cold. It pulls real strong at highway speeds, but will struggle when a load is put on it, such as a hill. It will idle just fine as well.Upon studying my factory service manual, I'm tending to lean toward either the TPS, or the VAF, but not for sure on either.There is also no check engine light. Does anyone have the factory troubleshooting guide.? I'm sure this is not a ignition issue, tune up is recent, doesnt miss or idle rough. I've searched thru the posts for similiar problems,but not much help. I don't want to start throwing parts at it as money is real tight right now, so I must diagnose this problem correctly the first time.

[eurotiva]

I know you said "recent tune up". What kind of spark plugs did you use? And what are they gapped at?

[perucho]

Is it timed right?

[JohnGunn]

I'm sure this is not a ignition issue, tune up is recent, doesnt miss or idle rough.

You're setting yourself up for a world of hurt when you start by announcing that the most likely source of such a problem, ignition, is beyond suspicion. New plugs, at $10, are too cheap to think you'll save money by not replacing them, while you run after failing emission control modules which are much more expensive to replace, much more difficult to understand and test, and much less likely to be the problem.

John Gunn
Coronado, CA

[JohnGunn]

What it does is stumbles and bucks when pulling away from a stop or when turning a corner and its in 1st or 2nd gear.

...

I'm sure this is not a ignition issue, tune up is recent, doesnt miss or idle rough.

A second thought.

I would be amazed if what you describe as "stumbles and bucks" were the result of anything other than ignition misfires.

John Gunn
Coronado, CA

[scitzz]

Stumble and buck is what mine did when the TPS screws worked themselves out, but no problems on the hill....

This recent tune up, you didn't happen to use the cheapo depot 7mm wires that have a tough time staying on the coil, did you?

[kartracer46]

My guess is you need a NEW set of NGK's set at precisely 44 gap and the issue will most likely cease. It's only a 65 HP engine, you take one away and you are down almost 16 HP. I wouldn't discount the ignition system even if everything was new. If the gap and plugs are good, then check the disty, and coil. You may also replace the fuel filter, it may be full of mud and only letting a minimal amount of fuel through.

[hawg keeper]

Thanks for the responses, but it is timed correctly, that doesnt change. New cap, rotor,and NGK plugs and wires less than 20,,000 miles ago, fuel filter same. This is probably the best maintained car on here and until now the most trouble free! I must remind you this is an INTERMITENT issue, dirty fuel filters, bad plugs or ignition components don't go bad intermitently, at least with my expierence. I might add that it has also developed a long cranking/hard start as well, in other words takes longer to start, cranks longer than it should. Sorry if I sound frustrated, I am! Out of work right now, money tight, just can't afford to buy parts don't need.

[scitzz]

This is probably the best maintained car on here and until now the most trouble free!

That is a mighty bold statement

Any exhaust fumes? Burning oil, or losing water?

Oh, and you didn't say about the plug wires...

[Team Lightning]

How many miles does the car have on it?

[wybnrml]

Have you checked the air filter?

[festyfanatic]

I just had a similar problem on my 88LX..... hard cranking and intermittent bucking. I took it to my mechanic and he found a coil wire that was loose. Starts up quicker and runs a lot smoother.

[JohnGunn]

New cap, rotor,and NGK plugs and wires less than 20,,000 miles ago, fuel filter same.

20,000 miles. Maybe this is a good time for me to tell my story.

I had driven my car for 120,000 trouble-free miles. And, in that time, it had only missed once. It happened when the engine was cold and I was accelerating from a stop. I figured the spark plugs might be a fault and replaced them. Problem solved.

Then about 4 months ago I noticed a slight surging when driving at slow speed from one stop sign to the next. On the way home on the Interstate, I could feel that the engine was not producing the power it had when I started out that morning. Over the next days the problem got worse, quickly escalating to the point of bucking and surging whenever I tried to stop accelerating and just hold a steady speed.

When I got home I came to this site and searched for the word "surging". As you can imagine I got lots of hits. It just so happened that the first few I read talked about failing emission control units, Throttle Position Sensor, Vane Air Flow Meter, etc. I think that is what convinced me I was dealing with some complex emission control problem. And off I went.

I replaced the Throttle Position Sensor, the Vane Air Flow Meter, the Idle Speed Controller, the Fuel Filter, and all to absolutely no effect. As you may notice not one of the replacements dealt with ignition. All affected only the amount of fuel or air that was allowed into the engine. That made sense to me because I, just as you are, was convinced the surging and bucking weren't violent enough to indicate that the engine was actually missing.

Finally, in desperation, I allowed my mind to accept the remote possibility that my problem might have something to do with ignition. So I found a replacement coil, and some plug wires that looked new, and bought a new cap and rotor and installed them. Nothing changed.

Of course, I didn't replace my spark plugs. Why should I? The plugs I was using were the most expensive plugs Bosch made, Platinum Ir Fusion at $8 a plug. And they had been oh so carefully installed less than 5,000 miles before.

Do I need to tell the rest of this story? Well, I will anyway.

At absolute rock bottom, I told my friend Sid, that I was going to buy some new spark plugs even though I knew that was not the problem. He agreed with me. But I went ahead and spent $10 for a set of 4 NGK V-Power plugs, just a little more than the cost of one of my prized Fusion plugs.

I guess it took me less than an hour to carefully gap them and torque them into place. I took my time and throughly enjoyed the experience. Strange when you realize I thought I was just wasting my time. That was a few months ago, and the engine hasn't surged or bucked once in that time. In fact, there is only one problem left from that experience. I destroyed my Idle Speed Controller by soaking it in Throttle Body Cleaner, and the replacement, bought on eBay for around $60, does not fully close when the car is warmed up. I found another one at the junk yard the other day and tested it in hot water to find that it does close. Now, all I have to do, to put this sad experience behind me, is to put it in.

In the end, only you can, and only you should, decided what you will or will not do to your Festiva. That's the way I live my life and I wouldn't presume to expect any less of you. In fact, when it comes time for me to say what I think someone should do, I prefer to phrase it in terms of what I would do if I were in your situation.

At times I get the feeling that these exchanges get to be pissing contests, where each person is actually more interested in saying something about themselves than in telling the whole truth. In that mode, one doesn't want to say, "These problems are complex and I could very well be wrong, but this is what I would do if I were in you situation." At that point one wants to say do this and this and that will fix your problem. Then, next day, read what a fine fellow you are for being so smart. I know the feeling, even though I fight against it.

I would never say that I "know" new spark plugs will solve your problem, but I've spent a long time telling you I think they might. And, truthfully, if you do change them to no effect, I will be, in a way, disappointed -- an unavoidable risk one must be prepared to take in dealing with complex problems. But there are rewards as well. Eventually there is the possibility that you will discover the fine art of giving advice without giving offense, and, maybe even someday, master the ability to accept the failure of your best efforts without feeling you have lost anything of yourself in the process.

John Gunn
Coronado, CA

[hawg keeper]

Thank you all for your advice, especially what John Gunn wrote as it seems as though he had similiar issues. So this weekend I'll screw in some new NGK's, the ones that are in it still look new as this is a healthy engine, except for its current issue. Maybe a plug is cracked, not sure. Did replace the fuel pressure regulator as I thought maybe the diaphram or spring in it was getting weak. I put a known used one on from my spares, but had no effect. Maybe Im wrong but this sure seems like a fuel distribution issue and not a ignition one, stay tuned!

[scitzz]

I am still wondering what type of wires he used....

I have used, 3 times now since 93, the cheapy 7mm wires. Only because it was dire, and they were the only ones readily available. All three times, from autozone, the coil wire does NOT stay put on the coil! This most recent time, I actually used electrical tape to hold it in place, gobs of it, even.

So, that is why I ask! It is easily possible that IF they were used, they COULD be the problem.

My favorite saying is, diagnose, THEN replace!

Also, no offense intended, JG, but in my own experience, when I suspect ignition problems, the LAST thing I think is spark plugs, other than if they are fouled.

Which just goes to show, experience may not be worth a hoot, since that is what fixed yours

Still, again to you, John, you posted a GREAT way to diagnose starting problems recently, I just wanted you to know that I thought that!

Anywho, hope one of us can help Hawg here, since THAT is what this forum is all about, helping each other keep our little overgrown roller skates on the road!

Paul