mutiple codes, and q's

[ffemtcurrence]

ok ive searched and searched and got lots of different answers....anyway during the KOER test i get a 542 (O,M) Fuel pump open, bad ground or always on - - Power / Fuel Pump Circuits...now when the car is running technically is the fuel pump suppose to be "always on"?????? the car bucks, misfires (well feels like misfires not sure) while under cruising speed 55-70mph u can feel little bucks only when ur under a constant throttle position....and under the cylinder test it skipped a cylinder...it only tested 5...and then it gave me to 30 code which saying theres a problem with the 3rd cylinder....now i know this can be many things...and for the 25% goose test i get an 538 code....i replaced all the spark plugs, the sp wires, the fuel filter, air filter 6 months ago and the oil changed 1000 miles ago...and to top it all of my low coolant light wont go out even tho there is plenty of coolant...o and one more thing the CE has never come on....like i said ive tried searches and the biggest problem i worry about is my 3rd cylinder...any and all suggestions would be awesome guys thanks

-vacuum leak?
-fuel pump problem?
-engine problem?

 

[projectSHO89]

Ignore the 542.

For the 538, slam the throttle tot he floor and release. your timing is also critical as you only have a 1-2 second window to hit it.

Unplug the low coolant sensor - they go bad commonly.

As for the #3 concern, I'd start with swapping the plug and wire with another cylinder and see if the problem moves or stays with #3. If it stays, I'd run wet and dry compression tests. If those check okay, I'd look at the injector for #3.

Steve

 

[ffemtcurrence]

thank you so much

 

[ffemtcurrence]

and one more question with the low coolant sensor unplugged the computer doesnt change anything in the engine or anything

 

[projectSHO89]

and one more question with the low coolant sensor unplugged the computer doesnt change anything in the engine or anything

Nope. It's just for the in-cluster light.

Steve