Allright, I've been fighting with my moms car for the past two days and I"m at my wits end with it and need help.

1995 Pontiac Grand Am "Quad 4" 4 cyl.

She started home from work the other day and it started bucking and surging real bad, it was fine on the way to work though. It started losing power and then it would smooth out like nothing was wrong, then lose power again.

I ended up changing the cat out, it was locked shut and blowing chunks out of the tailpipe..and was glowing cherry red in the process. It still had no power after this so I took the muffler off to check it out....still no power and a rough idle. I changed the plugs and coils out and it idles ok now, but still does not have the response it should.

It will start decent but you have to peddle the gas for a second until it catches up. It will sit and idle decent but as soon as you put it into any gear it will start bogging down and backfiring and have no power at all. When it is out of gear you can rev it pretty high but it starts cutting out and backfiring adn the new cat is getting real hot, slight orange glow to it. I though it might have burnt a vale or bent a valve but there is zero noise in the engine, I checked it with my stethescope.

I've spent around 14 hours in the last two days fighting this thing and I am at a standstill.

Can anybody help a brotha out?

BTW.....The first person that says "swap a 6.0 in there" I'm going to reach through the monitor and strangle.....lol

Thanks for any and all help.

 

FYI the cutting out when revving it in P or N is normal. My S-10 and a few other 4cyl GM cars that I have dirven do that. Its a rev limiter that acts weird is the best way to describe it. The cat is going to get very hot thats how the catalyst activates. I dont know what tell you any further then that. Check teh plugs and see what kind of condition they are in that will tell you if it is running fat to cause excess heating of the cat.

Oh and swap an 8.1L in there, those are the shiznit.

 

You could swap...nevermind, LOL!

I thought if the cat was glowing it was due to too much unburned fuel. Maybe there is an injector that is sticking open or a plug not firing?
Check the injector/coil pack/plug connections maybe. Are there 2 cats or just a single?

 

junk yard maybe?? dude those quad 4's have to be the worst engine gm ever built

 

It has a single cat, then a resonator and muffler in the back.

It has brand new plugs (the ones taken out where a light gray color, but not wet), coil packs, boots and the module is working properly. I did not check the injectors, but it does have a rich smell to the exhaust, thats why I switched out all the coils and plugs. I thought it might not be burning all the fuel or was misfiring.

Is there a way to check the injectors? This car only has 91K miles on it and this is the first hint of trouble it has ever shown.


8.1 you say....hmmmmm it would be a hell of a 60 footer....lol

 

EGR. Its on the TB and probably has CARBON like you woldnt believe. My 4.3l 6cyl had this problem and it turned out to be the EGR. I think its called the EGR. **** I dont even remember. ITs one of the damn sensors on the throttle body. And it made it run rich and that made the cat extremely hot.

 

i think its a TPS. we had them come in 3 or 4 times with the same problem.

 

That may have been it. TPS It had a crap load of carbon on it and it cost like 75$ at the parts store. lol

 

they get really crudded up. you can sometimes clean them. but in my experence. just replace it.

 

Also check the coil pack on top of the engine, they separate/crack and cause random misfires quite often, that would explain the unburned fuel.