01 3.8 having TPS and MAF codes and stalling
 

My wife has an 01 monte carlo ss with the 3.8 NA not supercharged. We bought it used and it had been wrecked before it seems. Well we've had nothing but trouble with this one. I've put in a new battery, new alternator, it had a bad shake or miss I guess and then had a flashing check engine light for cylinder misfire, so we did plugs, wires, and coil packs. Then before the alternator it kept stalling every once in awhile coming off the highway, found out the alt. was bad changed it, and probelm went away for a lil bit. Then same thing stalling after coming off the highway or even on the highway. We were on the highway and it acted like it was having the brakes applied and we pulled over and it was off, turned around heading home did the same just died when it had dropped off throttle, and we checked it then had 2 trouble codes.

MAF sensor performance, and TPS insufficient usage or voltage I forget now.

I changed both of those, the TPS and the MAF sensors, all was well fot a lil while we actually did like a 60-70 miles round trip on the highway and several off ramps etc. no issues and then another around 120-140 miles round trip, same no issues. Then one day about a week later on the highway not 5 miles from home, same brakes being applied feeling and died, When it does that and you check the codes and it comes up with the MAF code the key will start and shut off right away once it's stalled, and do that repeatedly until you clear the codes with the code reader I have,

If the car dies and has the tps code, the car will start back up and run but die after only a short time driving as it did today, but again clear the codes and it's fine for a while driving.

Before doing the tps and maf sensors when it died it threw both codes together, after changing them it only did the maf at first, and now it did the tps only today

So my question is why? should I change those again or maybe swap the ecm? I don't have a multimeter to check them, I need to get one. I did change those with cheap brand units, should I change them with only good name brands like ac delco delphi etc?

I can get a used ecm for it for a good price but would it be worth trying or is this a common issue somebody else had?

Try the ground for the PCM first. It does sound like it's something electrical going on. Especially since you were having so many issues with the charging system, and all of these sensors.

where is the ground for the pcm be glad to check it as mentioned it has been wrecked so it's hard to tell what may have been worked on or hacked up before we got it.

Also anyone think maybe the cat. conv. could be plugging up? I ask because usually when you leave a redlight on the highway and get on the gas good it'll smell like hair burning in the car, and yesterday I did smell the famous rotten egg smell for the first time not sure if it was us or not.

The car had that terrible shake on acceleration and after the tune up it helped that alot but it still has it some, and also has some spark knock on ping under hard accel like up hills taking off or trying to pass on a hill etc. I guess that would be considered under high engine load?

Sorry for jumping around but trying to think of all issues to see if maybe it all ties back to one thing or maybe related.

on a side note we also have a bad vibration or something when going up hill or turning but only to the right and feels like a vibration thru the suspension, I did change the right axle because the inner boot was off and it flung grease out, I also changed the engine mount on the cradle at the same time and had to replace oil pan gaskets as well. The oil pan had taken a good hit and was bent pretty good we changed all that stuff.

The vibration you can feel the shake or rub almost and hear it, and as mentioned its usually only during acceleration and in most cases heavy load like uphill and turning right when going say 50 mph or higher on the highway. I figure I'll end up hanging the other axle, and hub bearings, I felt no play, but we bought all new inner and outer tie rod ends already and was thinking of buying new lower control arms with new bushings and balljoints installed since it seems to be cheaper that way. I also know it needs struts on all 4 corners and then an alignment, so I'm hoping that would fix the vibration deal. There was no play in the ball joints tie rods or bearings but the pass. outer tie rod has a visual bend in it.

The PCM ground should be right near the PCM on the chassis. There's another big ground if you follow the battery cables to the chassis too. I have mine moved around, so I don't think I can pinpoint them anymore to you.

Yes, your catalytic could be bad, and it could give you issues that seem like the car won't move, or feels like trans issues.

I was going to suggest hubs, glad to see you already mention it.

How much are you about to drop on parts and everything? Is a wrecked car, with all of this work worth it right now? You can keep chasing, and we'll keep helping if you need it, but I would start to question it.

honestly it's not worth it, to look at the car you'd never know it was wrecked we didn't until we looked up the car fax on it. The thing is though my wife loves the car she had one, traded it off for a minivan and then later decided she wanted her monte carlo back.

So for her it's worth it.

I always buy junk and fix it all up anyways but I buy older stuff, like an 85 monte carlo ss, 79 trans am 83 chevy 4x4 01 s10 etc.

I usually just do a lil at a time as much as we can afford. We already have the tie rods just haven't put them on, but waiting for the cash to try and get struts for all four corners, and to do the ball joints or control arms at the same time along with the tie rods I have so it only needs the alignment once hopefully. It may come down to waiting for everything, like buying 2 front hubs, the other axle, and the struts then doing it all at once. I think the back hubs will be ok, and can be done later. I really want to address the front since that issue seems to come from in the front and usually only when you turn. Biggest issues of course is the stalling and repeated MAF and TPS codes. I keep banging my head on the wall with those.

I did go out and buy a multimeter today as well so maybe next time I can pull up ow to test the ohms or whatever of the MAF and the TPS.

I figure changing front end parts should fix the vibration issues and having the alignment done, but the electrical crap eeehhhh maybe now though I can pin point the thing and get it fixed.


on a side note the car is pretty nice, has a lil over 120,000 miles showing very nice interior with leather eats front and rear, nice door panels, dash, carpet, outside doesn't have any rust or rot either, has some paint flaws, and couple dents but she wants to paint it later.

Well definitely check a few of the things noted, and report back.

If you tackle other jobs and have questions, let us know!