Soo the other day I was driving home and all of a sudden the rpms dropped and the vehicle bogged down from aboutn 2500, 3000 rpms to about 1000. When I went to accelerate again the rpms dropped kicking me out again kinda like when my tps sensor went out. Also about a week or so prior when I tried to get up on it, the vehicle began to stutter and would accelerate like normal. I'm assuming these are connected. Eventually the check engine light comes on and it throws a o2 sensor code as well as lean oxygen, BARO pressure switch, and MAF. I Installed a new map sensor as well as a new tps sensor. Also checked the fuel pressure and installed a new fuel filter....what else could it be? It's kicking my butt...any info is appreciated! Thanks Trae

 

just a stab in the dark here, but i would check the distributor, injectors, and the mass air flow sensor, as well as all the wires/plugs to any of the sensors shorts can cause some funny stuff to happen

 

Already tried replacing the MAF(map sensor) didn't work. The injectors look newer, but Could the distributor cause problems like this? Also forgot to mention that it only kicks me out in 1st threw overdrive park and neutral I can take it to whatever rpms I want

 

Did it feel like it was downshifting? its kinda tell by your description.

Which car/engine was this in?

Make sure your TPS is at .54V (if you havent already) and ohm out all your injectors. They should be anywhere from about 17-22 ideally, NO LOWER than 12, and even that is pushing it. They should also be within .5 of each other, so if there are any that are past that they need to be replaced.

To test each of the sensors- unplug them and take it for a test drive. The car wont run 100% obviously, but if the rpm problem goes away youve now narrowed down your problem to its likely source. Id start with the MAF, then do the O2 sensor (one at a time).

What was the fuel pressure?

To me it sounds like you may have a failing injector(s). Ive HEARD that if one injector fails it can actually take an entire banks' injectors down, but dont take my word on that. Also remember to test them while the engine is cold AND when its warmed up.

Either way, ohm the injectors out first, then go from there. Hope this helps!

 

I personally dont think its the distributor, if it was you should have the problem constantly, not only occasionally.

Either way, try unplugging the sensors in question and see what happens. It could still tell you if theres a problem associated with it.

Still should ohm out injectors. Just because they look good doesnt mean a thing lol

Have you checked timing? Does it do this when cold too, or just warm?

Have you checked transmission fluid? Do you have any tranny problems?

 

It's the 91 GTA 5.7. It does it warm or cold I can pull it put of the driveway and if I accelerate under 1500 it's fine but as soon as you hit around 17 blehhhhh it drops. The fuel pressure was at 45 when off and when we ran it. Guess your right about the injectors lol I was just implying that they look newer Ima have to check the injectors and idk if it's the sensors like I said I replaced Em, but could they not be getting enough juice? And as far as the tranny not really it kicks a little in second but that's about it. And yes it tranny fluid.

 

Oh alright. Did you replace the O2 sensor? Baro?

Id say ohm those injectors, then we'll go from there.

After replacing those parts, did you clear the codes? Did any come back? If they did, did you run the new one(s)?

 

checked the ohms and the number one cylinders injector was measuring at 13 ohms the rest at 17. unplugged it to verify and she ran great...

just finished pulling off the plenum, runners, and replacing it...shes running like a top! thanks my dudes!!! the help is greatly appreciated!

 

Glad to hear it! See, just because the injector looks pretty doesnt mean a thing lol.