96 Sunfire GT rough Idle no power and sucking gas

[briand212]

I have a 96 sunfire gt 2.4 5 speed manual.
currently my car is idleing rough, has lost significant power when accelerating, and is going thru gas like mad. no engine light
History
My car started running rough on the way home about two weeks ago.
I noticed the next day the catylitic was glowing red so I figured hey bad cat and replaced it. this did not fix the problem new one is overheating as well.
I went to advance auto parts and they hooked up a scanner but there are no codes set
I have tried cleaning the injectors, changed the spark plugs, cleaned the throttle body and checked all the vaccum hoses, including the map sensor hose.
I have ohmed out the injectors and used a noid light on the harness
I have backed probed every sensor I could but still cant find the problem.

I am not sure how to check the egr or timing ( dont have a scanner)

Any suggestions would be GREATLY appreciated

[hotbug1776]

perhaps you got a bad coil pack, it's tough to check them because of the idi cover, but I believe it's possible.

that would be my next guess.

[briand212]

I checked the coil packs per the manual and they checked out ok.

[hotbug1776]

how many miles, and has the timing chain made any noise? what about a compression check? Did you check and clean the IAC? If you did, did you move the IAC? It could have damaged the servomotor if you did. After all, the IAC controls the Idle mixture, and can affect the off idle mixture as well.

the timing is computer controlled, as is the EGR. IF the chain jumped (should have been preceeded by some noise) a tooth, I dont think it will smack the piston (it might though, as you have a zero clearance motor) but it will make a power issue occur.

A lot of "if's" on this one. it needs more attention though.

Heck for that matter, the balance shafts may have jumped a tooth, you can never tell. Run down the list and keep checking, it's bound to be there.

[xtremamu]

Check plastic coil housing (tower) You will most likely find a burnt spot.. or at least smell a burnt smell. It seems to be a common problem. but dont find much info about it.. The part is not very expensive and easy to change..

[ThePrairieProphet]

another thought, i had some major issues of a similar nature with my car a few years ago, the 97 2.4. After numerous diagnostics, they sent of an advanced diagnostics to some GM place and it turned out that my EGR valve was staying open just a few percent, which went unnoticed most places, and set off wrong codes in my computer. They replaced the EGR valve and fixed the problem.