my car was making a kinda grinding noise on the way home the other day and the next day when i went to start it it starts but the engine makes thumps when gas is pressed and looks like the engine is jerking when hood open. i am getting errors:

11 Intermittent loss of either camshaft or crankshaft position sensor,/No crank reference signal detected during engine cranking/Timing belt skipped 1 tooth or more from initial learned value,

43 Multiple/ single cylinder misfire


21 02 sensor problem (oxygen sensor), upstream or down stream

13 No change in MAP from start to run

i brought it in and they cant figure it out. they thought it was the timing belt but timing was fine. they also did a compression test and was fine. any i deas what else it could be cause the shop is out of ideas and i know very little about cars. it is a 95 dodge neon sport 5 spd.

thanks for any help

 

The biggest indicator should be the code 11. The timing belt is supposed to be replaced every 105k miles max. I'd say 80-90k if you've ever had overheating issues or drive the car hard. If you are near that mileage, replace the timing belt, water pump, and tensioner before something breaks and you are into some serious money. How the heck did they determine the timing was fine? It's not like you can hook a timing light up... you have to remove the outer cover and make sure the marks all line up.

The code 11 could also be a bad/out-of-place crank sensor, whcih tends to cause a bucking/jerking syndrome. The sensor runs $35-40 last I checked, but I wouldn't bet that it's the real problem, particularly if the timing belt is due.

The code 43 could easily be caused by a skipped tooth on the timing belt. I got that code after skipping 2 teeth...

The other two indicate sensor issues. Autozone will scan for 4-digit codes, which will narrow down things quite a bit, like exactly what is causing the code 11, and which O2 sensor is the problem (so you only have to troubleshoot/replace one of them...). The MAP should be pretty cheap ($15-20) and very easy to replace. Both the O2S and MAP will cause idle/driveability problems.

So here's my suggestion - head to Autozone or some other place that will read the 4-digit codes for free. Pick up a MAP sensor and the appropriate O2 sensor, along with an O2 sensor wrench and some PB Blaster (helps loosen rusted parts). After those are installed, reset the PCM (or disconnect the battery when working on the sensors like you should...), and see how it goes from there. If the 4-digit codes indicate a problem with the crank sensor, you can either buy a new one and install it yourself (recommended) or go back to the shop with the new information and see if it's just out of position a tad (labor will be more than the sensor...). Keep in mind that there could also be a problem with the wiring for the sensor, so look for places it might be rubbing (like the axle) or getting pulled tight. Then, if you are due for a timing belt, head to www.boogerracing.com and read Jeff's how-to on timing belt replacement. If it's something you think you can handle, go for it (don't forget the water pump). Otherwise, a shop will run $300-500 for the job.

Best of luck!