98 Escort ZX2 stumbling and hesitating....making noise

I have a `98 Ford Escort ZX2 that is having serious issues. When you first step on the gas, it hesitates badly. Upon acceleration, it stumbles badly, and occasionally "pops" which sounds almost like an intake backfire. The problem has been getting worse, and the "Check Engine" light which would start blinking periodically is now blinking more frequently. The exhaust smells rich to me. I`ve already checked the spark plugs and wires. Fuel filter and air filter have been changed. I have tried different kinds of gas with none of them making a difference either way.
Any ideas what this might be? It seems to get slightly worse after the longer the car is driven. Could this possibly be the timing belt about to fail? Is this easy to check/replace? I know it hasnt been changed for atleast 60,000 miles.

does it jerk really bad? u said u checked the plugs and wires ...so there getting spark? is the mill light setting a code?

oo and the easiest way i can think of to check the timing belt is to pull off the cover on top of your engine (valve cover) to expose your cam gears. and see how its looking ...the other way is to rip it all down like you were to change it. hope that helps some

does it jerk really bad? u said u checked the plugs and wires ...so there getting spark? is the mill light setting a code?

Hi,
Thanks for the quick response!! I wouldn`t say it jerks really bad...nothing that would hurt your neck atleast. It feels as if one of the spark plugs is fouled out, if that means anything. Its like the engine is stuttering. The strange thing is, I replaced the spark plugs, and it drove much better for a while, though still stuttering and hesitating a bit.

oo and the easiest way i can think of to check the timing belt is to pull off the cover on top of your engine (valve cover) to expose your cam gears. and see how its looking ...the other way is to rip it all down like you were to change it. hope that helps some

I am assuming the valve cover isnt too bad to do? Does it involve just loosening the bolts up top, or is it going to be a major ordeal? I did change my valve cover gasket on my 89, and it was cake. Is a timing belt change something that can be done in an afternoon?
Thanks.

What's the fuel pressure? It could be overcharging. Also, It possibly could be a bad fuel injector. This just sounds like a fuel system problem to me.

The timing belt won't cause any drive symptoms before it fails unless it slips time. Which would cause symptoms all of a sudden and would not become progressivly worse over time.

Just a thought, If you unplug the cam sensor does it go away?

-Mark

What's the fuel pressure? It could be overcharging. Also, It possibly could be a bad fuel injector. This just sounds like a fuel system problem to me.

The timing belt won't cause any drive symptoms before it fails unless it slips time. Which would cause symptoms all of a sudden and would not become progressivly worse over time.

Just a thought, If you unplug the cam sensor does it go away?

-Mark

Is the cam sensor the sensor right on the top of the valve cover? Is it safe to run this disconnected?

Yes that's the sensor. The PCM has a "failsafe" in case the sensor was to fail, in which it runs only off the crank sensor. It will trip p0340 though when you unplug it.
The ignigtion is basically controlled by the crank sensor. The cam sensor adjusts the ignition timing based on the variable camshaft position. If it's unplugged the engine runs in a "basic" ignition pattern eliminating the variable camshaft and the advanced ignition principles.
This will help to determine if there's a problem in your valve timing, if it runs better then the problem is most likly in the head/or timing. If it still runs poor then start chasing down fuel mananagement, airflow, possibly ignition but I highly doubt it because the coil packs last forever and you replaced the wires and plugs already.

Basically it feels like the car has lost about 20hp when this is done because the VCT goes back to maximum retard just to elimate any potential spark knock, or detonation just in case something actually was wrong with that circuit.

Hope this helps,
-Mark

what mark wrote sounds better than what i was thinking. a buddies dad showed me that if u put a flat head screwdriver on the top of an injector u can feel it "ticking" . all your doing is feeling for the injector to open and close. u might be able to try that.

I had the same problem develop not long after I replaced the timing belt. Later it turned out the belt was off one tooth, and I corrected it and replaced the spark plugs. The problem went away and it drove great - but not for long.

If the problem is the same, I've found that it runs normal while the engine is cold. After it warms up, the misfire starts and I get the blinking MIL. I use the ELM32 OBDII system with my computer, and it doesn't find any recorded codes. Clearly it has to do with the ECM controlling the timing, as the service manual describes the ECM going into closed loop state after the engine is up to temperature.

The suggestion about the crank position sensor is a good one, I plan on taking a closer look at it.

Thanks everyone. It does seem to run just a little but better when it is cold, but not by much. I tried unplugging the sensor, and nothing changed. :( I removed the cover on top of the timing belt, and it felt like it had plently of tension. There is some very minor cracking along the outside of the belt, but not too much. I also checked the spark plugs, and besides some carbon buildup, they look normal.
So I am guessing the problem is somewhere in the fuel system. Supposedly the fuel filter was changed about 15,000 miles ago. If anyone else has any suggestions, please let me know.

**ALSO......

I just took it out again tonight for another drive. After about 15 minutes of driving, I noticed the catalytic convertor is glowing bright red! There is also a severe exhaust leak right around the firewall where the down pipe connects to the cat-back. Could this be the cause of the problem? Would the car run rich from an exhaust leak? The pipe is almost completely severed.

well if the car had a EGR that could be the problem. but i have a 98 zx also and im almost sure that they dont have one...like mark said maybe the fuel system is over charging and not burning all the gas..ill talk to one of my college teachers and get his input for ya. he has a nack for trouble shooting

-Dan-

Nah there's no EGR on a ZX2 they have the VCT on the Exhaust cam to mimic the functions of an EGR. Also, a bad fuel filter would have the opposite effect.

As for the Exhaust leak. The Ford book I have does include exhaust system checks as a diagnosis of a rich condition. I suppose if it's upstream of the o2 sensors the extra air getting in will cause the sensers to think the engine is running lean so it will add more fuel. Which is supported by the carbon on the plugs. However, on personal experience, I had a "great" car that had one bolt holding on the exhaust manifold on the engine, so a major leak, and it caused no drive symptoms other then noise. However, It only had throttle body fuel injection, or as I called it a "fancy carburator" and OBD-I. So It may not even compair. However, I suppose it makes sense because the PCM doesn't rely on the O2 sensors until the car is warm.

-Mark

mark what woud make the cat glow red? i talked to my teacher and he was not much help.. all he said it that it could be a # of things...

I've never run into that before. I would assume that there's excessive heat in the exhaust. Like maybe the exhaust leak is causing some afterfire and it's burning the rich mixture down through the manifold or perhaps in the catalyst. Like in Nascar when they crash and refire the engine, fire burns out the exhaust because of a puddle of fuel in the header.

I don't think that's the problem just a symptom of the problem exaggerated by the exhaust leak.

-Mark

mark what woud make the cat glow red? i talked to my teacher and he was not much help.. all he said it that it could be a # of things... Sounds like your converter is plugged.

I have a 2000 escort zx2 that i went through the whole car.i see many problems on here that usually are a result in a bad timing belt.if you are experiencing mis fire popping and want to check the belt to see if it jumped timing. Stop and do not continue to start that engine!!!the engine is a interferance engine.you will bend the valves....in order to check the timing your self you have to pull off the valve cover turn the engine over by hand until the slots of both cams line up evenly with the edge of motor going across from front to back these are located drivers side,which is the back of the engine.pull out you number one spark plug and check to. See if the piston is at the top.then you want to crawl under the car and locate the timing marks on the crankshaft pulley.they are real small slots.i made mine larger to see for future replacement.the marks have to be lined up on the pointer located on the timing cover.you have to make sure cams are lined up perfect with the crankshaft pulley marks.i do not recommend you replace the timing belt your self unless you really know what your doing.these motors are very reliable.also don`t run low grade fuels.you lose money in the tank and your vehicle burns dirty and poor gas mileage/performance

My 98 zx2 does that jerking thing you were talking about i need to say my ignition was ripped out so it is hotwired. I thought maybe it could be a electronic issue or fuel im pretty much lost um any suggestions so I don't do something stupid

Fuel pump I was Sinostumped to it's under back seat