Two typical car problems?
 

1. A friend with a Suburban has been dealing with a rough idle. He had the fuel injectors replaced as well as the plugs. He has run Seafoam through the gas tank. I checked his codes and he had a misfore on cylinder 1. His fuel trim numbers look good. I think he has either a valve issue or a coil/ignition issue. When I was there yesterday, it was running a little rough but not too bad. He said that he just recently ran seafoam through the oil as well. I'm thinking he has gunked up valves. Comments?

2. Our Tribeca just had the 60K miles service done. Included was a brake fluid change. At the same time, we needed the rear pads done. Now the brake pedal is vibrating slightly and especially when the car is cold. It does it when in park so I know it isn't the rotors. They did switch from DOT3 to DOT4 which should be OK for this car, assuming they drained all of the DOT3 out. Maybe they didn't fully bleed the lines or maybe there is a vacuum leak now? Comments?

Re: Two typical car problems?
 

What year is the truck? Mine is 99 with the 5.3 has some funky stuff (random missing) every once and awhile. I tried swapping coils injectors and i even had the vavles adjusted and the mechanic had it for 2 weeks and all of a sudden it started running good again. im thinking my needs a computer.. but if i was you try swaping the coils around seeing as ur misfire is only in cylinder # 1 if the miss changes cylinders when coil packs are swapped there u go buy a new coil good luck man!

Re: Two typical car problems?
 

I'm not sure of the age but I don't think it is that old. I think it is early 2000s. The fact that it has improved markedly with Seafoam in the oil leads me to believe that it is a compression issue most likely due to gunked up valves. I suggested that he step up the cleaning at the next oil change by putting Auto-RX in with a decent high mileage oil. I then suggested that he stick with high mileage oils for the time being and either switch to premium fuel or use Seafom in the gas at least once per OCI.