jayboog5000

2002 malibu 3.1L 143K first off the car runs perfectly most of the time only when the car is under increased load does the problem appear. (I have already repaired the IAT wires) first the temp will rise slightly 10-15 degrees then the engine will run a little rough (it idles fine) when stepping into it the engine will miss very consistently like its one or two cylinders missing if you let up on the throttle it runs better, pressing it down more makes it worse, if i just barely lay my foot on the gas its almost unnoticable but if i press harder it comes right back also the rate at which i apply the throttle seems to have some effect faster=bucking slower=smoother but there is a point when it does not matter (1/3 throttle) if i give it full throttle the engine wants to stall and has a few times this is all very intermittent and if i let the car cool down (idle for 2 mins) to the normal temp the problem goes away in a few minutes there is no codes and no check engine light it seems to be a problem with the TPS or MAF but could a few degrees of coolant temp really make this happen? please help if you have seen this before I dont want to end up stuck somewhere

mattdez

It could be the fuel filter or fuel pump. Try replacing the filter first since it's easiest (and less expensive).

jayboog5000

so I finally fixed the AC copmpressor and now the cutting out problem happens within 1-2 mins at idle and continues until i turn the AC off and cool down a but with the problem occuring almost all the time I tested several sensors with the problem happening and without. the following sensors are ok MAF, TPS, CPS A, CPS B, CamPS, CTS, I also unplugged the EGR and tested Fuel pressure both with no luck but I did notice some corrosion on the negative battery cable and the resistance seems to jump alot from o.o ohms to 200 ohms and everywhere in between but that doesn't seem to affect the cut outs and I also connected a jumper cable from the battery to the block and got a steady resistance of 15 ohms but the engine still cuts out I will replace the cable anyways and repost my results... fingers crossed

jayboog5000

so i replaced the ground cable and it was better for a few days but now its back i was able to hook up a solus to the car and saw the cam signal cuts out when it happens and the 3x engine speed jumps all around but both sensors are ok on the oscope is there something im not getting here? i checked the wiring around the front of the engine found nothing any suggestions have you heard of this?

jayboog5000

so I replaced the cam position sensor and no luck. on the snap on solus scanner the 3x engine speed is ok but when the problem occurs the 24x engine speed value looks like a slot machine window all digits just randomly changing this is what throws the ignition timing off and makes it run crappy I thing the signal is the one that goes through the ignition control module so I have already checked the signal going into the module but not going out back to the ecm I will test that tonight and see what I find im starting to suspect to PCM because I also get a fault in communication code but the car still runs fine when that code comes up