Join Date: Apr 2017
Serrasalmus13 is offline
Need Help Troubleshooting - 95' Sonoma 2.2L
So I have a 1995 GMC Sonoma 2.2L ,Automatic trans, about 200k miles on engine- that developed an issue a few weeks back. I have been troubleshooting, and really learning alot about the truck as I go, but I cannot figure out what the problem is with it. I was hoping maybe you guys could throw some ideas at me or share any wisdom here.
Here are the symptoms:
The truck starts up, runs but idles kinda rough. Its a steady idle, but it does shake. Initially when I start it, if I give it some gas while its idling it will choke and the rpms go from about 1k down to zero and die so long as I have the gas pressed down. If I let go of the gas before It fully dies, the rpms go back to 1k. If I let it warm up, and then press on the gas it will hesitate but then rev up the rpms like normal. If I shift it into gear, it will run, but if I give it gas, the RPMs go up but the truck will not have any power at all. It will just drag along. I have a hard time getting it over 20 mph. It does shift gears but it takes it a while to get up to speed. Like I said, it is extremely slow and pretty much un-drivable. It also makes an extremely loud engine noise when I give it gas. Now, I have an aftermarket intake installed on the truck, but the noise that it makes is like if I was in a tunnel amplifying the sound.
More background information: When this first started failing on me, I was driving it fine and I heard a crunching noise like if ran over a can of pop. From there the engine noise got louder and I experienced the lack of power. I limped it home and have been troubleshooting it since.
Here is what I have done so far to it:
Replaced the EGR valve
Replaced Map Sensor
Replaced spark plugs and wires
Replaced coil packs
Tested and checked to make sure wires and plugs all working correctly
Replaced IAC valve
Tested TPS sensor with a multimeter
Replaced Fuel filter
I thought that the problem could very well be a clogged part in my exhaust/cat. The problem with that is that some of the testing I have done for that has come up indicating that is not the issue.
I did a vacuum test and got it to about 14 units pressure steady (which seems to be a low reading)- If i increase the rpms the pressure drops but it starts to rise after a while, which I thought was weird.
I also removed the O2 sensor from the exhaust header before the cat and the car just ran really rough then. I figured I could see if it would give me some of my power back, but the idle was way off and the engine sounded like it was going to die so I didnt try and move it.
I guess it could still be a clogged or partially clogged cat, but of course I dont want to spend money on that if I dont know for sure.
I'm not really sure what else it could be that would cause all of these issues? Perhaps an issue with the engine? Valves? Timing belt? Injectors? Failing fuel pump?
Another strange thing with this is that I have no check engine light. I used to have a check engine light since I bought the truck, but a while back the light went away well before this all happened.
I have no OBD tester, and i've read that this year GM vehicle requires a specific OBD scanner anyway, so I have not pulled any codes or anything like that. I will try to get the codes from the relay I guess, and update this soon.
I appreciate any feedback, and if I left out anything or if you have any questions on this please let me know!!
I will be updating as I go!