Okay guys, it's me again. what is the deal with my car, I spent over 1000 dollars on diagnostics and parts for this to solve but is still the same.

I have a vibration at 40mpht to 55mph. there is no vibration before that or after than (maybe slightly after 55 but feels like it disappear).

also i have a vibration also when parked! around(1500 rpm disappear and comes back at 2200 rpm)

parts I replaced:

diagnostic(dealership) $120 (no codes no problems)
replaced opti
replaced wires
replaces plugs
diagnostic at the transmission shop (no codes no problems)
replaced torque converter ($500)
cleaned injectors through the fuel rails ($80)
balanced tires
diagnostics(engine mechanic shop)(no codes all okay)
they suggested engine mounts but not sure and quote me 500 to change out engine mounts.
note: they told me engine mounts look good but it could still cause the vibe but again not sure
rebalanced driveshaft
cleaned MAF
cleaned TB
cleaned AIC

so guys what the hell else is wrong


PLEASE HELP

 

I had a vibration right around 45 mph that would come and go. It was caused by the engine. To make a long story short, what finaly cured it was the IAT bypass. Simply buy a 4.7k resistor at radio shack, plug it in instead of the IAT, and wrap it with tape.

 

How bad is the vibration, was the vibration present before or after the opti swap? You maybe experiencing engine harmonics. Try rotating the balancer hub (not the crank pulley) 90 degrees at a time, then drive the car to see if that cures the problem.

 

vibration is there before the opti install. what do you mean by engine harmonics?

where is IAT at and can i do this easily? pictures would be appreciated. what does IAT do and bypassing it,, what does this do. thank you.

 

for the iat bypass what do i do with the sensor after? thanks

when you say plug it in istead of the sensor, do you mean pull the whole thing out of the elbow and stick the resistor inside the hole or just pull the clip off and go from there?

 

Just pull the clip off, and plug the resistor into the connector. The sensor itself will stay in the elbow.

 

completed and tried to IAT bypass and problem still the same. Now im experiencing a pop from the exhaust under load, im talking about 5mph then letting off the gass it "sometimes" pop. not all the time though.

whats the posibility that it could be the coil? can a coil make the car vibrates or have this pop sound in the exhaust?

if its the coil, how much is for the part? thanks guys

 

http://www.gmpartsdirect.com/results.cfm

is this the coil i need to replace with?

 

Pop the hood open in darkness with the car running and see if you can see any arcing.

 

sorry for the inexperience question but what is arcing means?

do you mean pop the hood and have someone start the car and see if there is any arcing? OR

start the car, and during idle look at under the hood to see if there is any arcing?

where would be the arcing located and what is it? thanks again.


UPDATE:

I went to a very dark place and have my girlfriend started up the car and then look around during the cranking the engine to start up. I saw a light which in color blue in a straight line by the coil. about maybe like 2cm long and disappear after the car started and never came back. I dont know if thats normal or not. but other than that there was no lights under the hood or maybe im just looking at the wrong places. where should I look?

 

Arcing is tiny spikes of electricity. Start the car in complete darkness, pop the hood and look for little blue lights flickering around the sparkplug wires, coil and the optispark.

 

I did not have anything flickering just during when the car is beggining to start. there is a blue light at the coil and then when the car turned over (start) it disappear, is this mean i have a bad coil?