Hi guys, I'm currently having some problems with my 97 Z24 Cavalier. The main issue is that it stalls if you give it gas too quickly. It seems to only do this at low RPM. Above ~2500ish RPM you can punch it and it won't cut out but below that it will unless you lay into the throttle a bit slower to get above that ~2500ish RPM threshold. It also has a bit of a hard starting issue sometimes requiring the engine to turn over for a few seconds before firing. I started a thread back in November about this problem that got a few responses, but I didn't have the time or money to pursue the problem at that time. One guy suggested talking the vacuum hose off of the fuel pressure regulator and seeing if gas spits out. I checked that and gas does not come out. The other response I believe was from MD Enforcer and he suggested to look into a CASE Relearn. I looked into that but it seems only dealerships or possibly people with scan tools can perform that procedure. I don't really want nor do I have to the money to take it to the stealership or to buy a scan tool. However I do have a OBDII code reader and the check engine light is on. The two codes that repeatedly show up after clearing them and resetting the PCM by unhooking the battery for extended periods of time are as follows:

P0335-Crankshaft Position Sensor A Circuit

&

P0341-Camshaft Position Sensor A Circuit Range Performance (Bank 1 or single sensor)

I have only troubleshooted and replaced a few parts so far. I began by replacing both the CkPS and the CmPS with no positive results. Then I checked continuity from the Ignition Module to the Crank Position Sensor and there seems to be no breaks in the wires. When resetting the trouble codes the Crank Position Sensor code (P0335) always shows up first before the Cam Position Sensor code (P0341) is thrown.

The next and last thing that I have checked and replaced this time around were the spark plugs as the electrodes on cylinders 1 and 3 were worn and shorter than cylinders 2 and 4. These plugs were about 5 years old and needed replaced regardless. I also replaced the boots that go from the coil housing to the plugs as they were falling apart. None of this helped the issue either.

About 2.5 to 3 years ago I had the wonderful experience of replacing the water pump on this 2.4L. I have read some guys had similar running issues with the timing chain being one tooth off. I don't believe this is the issue in this case as the car ran great up until this last issue that I'm currently having. The same time that I replaced the water pump I also replaced the fuel filter, ignition module, and the ignition coil housing which may be helpful for you to know.

I'm not sure where to go next. I'm thinking maybe do a fuel pressure test and/or change the fuel filter as it is a few years old. Any help and ideas would be greatly appreciated!

Okay so today I tested both the MAP sensor and the throttle position sensor. I checked the MAP sensor by progressively increasing a vacuum on it and watching the voltage decrease and it fell within parameters. I checked the throttle position sensor by watching the voltage through the full range of the throttle and it also is fine. The strange thing is that when i unplug the MAP sensor and start the car the problem with it cutting out almost entirely goes away. It runs a rough with it unplugged no doubt but it doesn't cut out and die. Anyone know what this means? Could the MAP sensor be bad even though it seemed to test like it was working?

I would check your timing to be certain, with it throwing the cam and crank codes I would want to be certain everything is in time.

Is there a way to do this without having to get into the timing chain housing? That's a lot of work/money for gaskets to just check and see if everything is lined up correctly. >:o

I forgot to add earlier that if I clear the crank and cam position codes before unhooking the MAP sensor they are not triggered. The only code that shows up then is for the MAP sensor, obviously since it is unplugged.

This forum really died. Do people go to another website/forum now or is the low traffic due to these cars getting to be a decade or two old?

So I went ahead and bought a fuel filter, sea foam, throttle body cleaner, and I rented a fuel pressure tester. Itll probably be a day or two before I can get to it. Ill post what happens. Any other suggestions in the meantime would be greatly appreciated.

I got to work on my car a bit more today. I did the fuel pressure test and everything seems fine although I wound up tieing into the system back at the fuel filter rather than right before the fuel rail as it would have been a major PitA to do it that way. I also replaced the fuel filter which didn't change anything. I pulled the fuel rail off and ohmed the injectors which all seemed fine. While I was in there I replaced the o-rings as some were pretty nasty looking and spraying throttle body cleaner around the injectors with the engine running seemed to cause it to sputter. I also cranked the motor over and they all seemed to be spraying fuel properly. I moved the factory battery ground point as it was all rusty and corroded, once again no dice. I also ran sea foam through it and cleaned the throttle body and all the vacuum ports thoroughly with throttle body cleaner.

So none of that worked at all. I think the next thing I'm going to do is try to check out the PCM, maybe unplug connectors and look for corrosion if I can get to it. I've never messed with the PCM before so I don't know how difficult that will be. If that doesn't work I guess I'll be moving on to checking the timing as I really don't know where else to go.

The connector for the engine coolant temperature sensor is full of oil. I don't know how much of an issue that would/could be. It's not throwing an ECT code.

I'll post results in a day or two or three if anyone is curious.

Any help/ideas are greatly appreciated.

I have a 97 Z24. Mine runs fine with no hessitation when hitting gas. It sometimes takes 2-3 seconds to start when engines hot. A few weeks ago it was stumbling a little on startup after I ran the AC one day but it had bad gas in it that I since ran out and replaced with 93. That did the trick. It used to idle rough and sometimes die until it warmed up but new plugs and boots seemed to have fixed that. I read that replacing O2 sensor can fix some of these symptoms. I'm going to replace that sensor to see if it helps any because 198xxx miles. Might be something cheap to look into. good luck

By the way I dont know how to take off the intake manifold cause theres a hard to reach bolt at the front. does it take a special tool? or else I would clean and polish my throttle body. I also dont know how to disconnect the lines/hoses either but.

So I looked at the PCM connectors today and they look fine. I guess the next step is checking the timing.

I'm going to take the ignition control module in to have it tested while I'm there to rent a puller for the crank pulley.

Does this sound like a timing issue? I just don't understand how the timing being off would cause this. I can rev the crap out of it all day as long as its above 2k RPM and it also idles just fine. It just that small window between 850ish to 2kish RPM where this is happening.

Well it's fixed now. I ended up replacing both coils and the coil housing, although it looked fine and was only a couple of years old. I put dielectric grease on all of the parts of the ignition system that make contact with one another. No more hard starts, no more stalls at low rpm WOT, no more check engine light.

After digging through various forums I managed to find a few similar cases to what I was experiencing. I mean hours of digging, most of them with few or no responses kind of like this thread. They all were fixed by replacing various parts of the ignition system. If anyone else is having similar problems and codes being thrown that you have tested and know that they definitely are not the problem, I would suggest looking at/changing these parts: spark plugs, spark plug boots, ignition coils, and/or the ignition coil housing. I've read some bad things about the coil housings used on 2.4l's being bad internally where you can't see that the damage is causing arcing to other pathways inside the plastic. It doesn't hurt to take your ignition module to your local parts store to have it tested while you have it off too.

Hopefully this helps someone else.

Take it easy folks.