Low Compression? Or Not?
 

Hey guys,
I have a 2007 Colorado with 210,000 miles. Engine light came on, auto store pulled codes and it was for misfire. Put in new plugs. Old ones had probably close to 100,000 miles on them.

The truck would not start, had backfire issues through the intake. Re-did the plugs multiple times, finally had it towed to a professional shop.
Their diagnoses was low compression on cylinders 1 and 4.
1 = 60psi
2 = 190psi
3 = 190psi
4 = 135psi
Rebuild or replace was their options. Had it towed back to my house and it sat. 2 weeks later I turned the key and it is workng just as it once did.

Everything seems ok. I stopped to buy some Engine Restorer or something similar, but after reading the bottles, I don't seem to have any of the symptoms listed. I am not burning oil, smoking, or feel much of a loss of power. It seems to me the 60psi cylinder would be making the new oil dirty or causing smoke or causing a rough idle or something.

I am thinking the new plugs blew cabon build up every where inside the motor and maybe caused valves to stick open or something.

Has anyone seen or heard of this??

Thanks for reading all that,
Bo
Houston, Tx

If you had low compression you would definitely feel the engine not working right. I had a 95 berretta with low compression, the engine would skip, studder, hesitate. But after driving it for about 40mins the ECM would shut those cylinders down, and it would be a smooth ride from then on. I would take it to another shop to have them test the pressure, just to make sure your ECM isn't shutting them down.

It could also be your piston rings are shot or your valve (s) has a crack or a hole in it...but it would most likely be the valves sticking..pm me and let me know what ya found out