Engine problems...need help pls

[AWD]

at cold start up on my ty it has a rough idle going between 1000 rpms and 2000 rpms, this does not change no matter how long i let it warm up, when i start driving it runs fine but the check engine light comes on and turns off throughout the drive.

this has gone on for about a week with no other problems, until now, when im running a/c or just the fan the truck shakes like crazy and has a very sketchy idle, and today it felt like i lost pressure in my breaks twice because i had to push very hard to stop..

the truck is more or less stock, just cap, wires, plugs, programing and a blitz BOV

any help would be awesome because im scared to drive it.. :tdown:

 

[GMPartsGuy]

Re: Engine problems...need help pls

I had problems similar to yours (although my idle wasn't quite THAT bad), and my rough idle turned out to be a stuck EGR valve. It was partially stuck open. I replaced it, and problem solved. I also had a check engine light that would turn on and off at different times while driving (usually on the freeway), and it turned out to be the oxygen sensor. Replaced it--no more check engine light. Although you'll have to pull the code from yours to see what your problem is, there's a good chance it could be relatively simple.

 

[dgoodhue]

Re: Engine problems...need help pls

If you have a check engine light, you should read the code set out of the ECM first..

 

[Flyin Ryan]

Re: Engine problems...need help pls

Def pull the error codes like stated above... also how's your vacuum lines? a vacuum leak could cause some crazy idle problems

 

[BacDoc]

Re: Engine problems...need help pls

Check the timing too.

 

[AWD]

Re: Engine problems...need help pls

i found the big problem, my aftermarket boost guage was tied into a main vac line and somehow came loose which would have cause the brakes/idle problem, but im still getting a rough idle until about 10-15 min into a drive, im going to buy the block plate for the EGR so im hoping that might fix it? anyways thanks for the replys

 

[typhoonTODDmontess]

Re: Engine problems...need help pls

If all the above suggestion don't help check the the brake booster, there is a check valve attached to it. If you pull it out you should here a air hiss, thats good, the booster will draw vacume from the manifold if the valve is bad or if tdown:the booster is leaking, but this deffinately sounds vacume related :tup:

 

[Flyin Ryan]

Re: Engine problems...need help pls

i found the big problem, my aftermarket boost guage was tied into a main vac line and somehow came loose which would have cause the brakes/idle problem, but im still getting a rough idle until about 10-15 min into a drive, im going to buy the block plate for the EGR so im hoping that might fix it? anyways thanks for the replys

How's the rest of your vac lines?? check the one from the map sensor also if there the stock ones you should invest in some nice silicone ones and zip ties so you never have to worry about them again.

Also what chip are you running? because if you have a stock chip and your disabling the egr you'll get a code off and on when driving.

I'd suggest the bike tire method to finding vac leaks.. you might have more then you think or possibly have a seriouly leaky throttlebody. here