Ive noticed my car has been hesitating at wot lately. Tonight coming home from work, anything beyond 1/4 throttle bogs down and the car runs like crap. I havent done anything to it lately except an oil change so I can see that i changed anything. I cant get beyond 2500. Is this the infamous "limp home mode"? Please help.

 

Maybe your fuel filter too.

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92 RS, 350, Street & Performance MPFI, TFS heads,
Crane Rollers,
MSD Digital 6 Plus, 22lb injectors,
ZZ3 cam, Edelbrock Headers 1 5/8, 3" Exhaust,
Hi Flow 3" Cat, stock T-5,
stock rear 3.08, koni yellow adjustable front, twin turbo glass hood, T-tops, Auto Meter Ultra Lite Series 2 5/8 gauges, Teal Green

 

replaced that about 3000 miles ago. Anyone else, please.

 

I checked the injectors and it seems to be shooting enough gas. when I floor it it bogs down, plenty of gas is shooting into the manifold, but it runs like crap. It wont go past 2500 rpm. It runs better if I keep it at 1/4 throttle, but I can go verty fast like that. Please give any suggestions you might have.

 

Eyeballing the injectors really isn't too accurate of a way to tell if enough gas is being sent through. Try checking the fuel pressure.

It could very well be a clogged fuel filter. Most of the symptoms sound right. It couldn't hurt to check anyways.

It might also be a clogged cat, or some other part of your exhaust.

Or maybe it's an incredibly messed-up o2 sensor?


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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

I replaced the O2 sensor about 5 months ago. I have noticed more of an exhaust smell lately. Would removing the cat help me diagnose it? How can I check the fuel pressure?

 

A strong exhaust smell? Hmm. I think that usually indicates a rich condition. When you changed the O2 sensor, did you reset the ECM?

FUel pressure can be checked with a fuel pressure gauge.. I think most parts stores (Advance Auto, Autozone, etc.) sell them. As for the exact hows of doing it, I'm not sure.

When you remove the cat, you can check to see if it's clogged. Also, a failing cat could produce a different exhaust smell.. Although usually a worn cat will produce a lovely rotten egg smell.



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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

If by resetting the ECM you mean disconnecting the battery for awile, I didnt do it right after changing it, but it has been done since then. I thought the smell indicated a rich mixture too, what could this mean?

 

It could mean that it's running rich. hehe. Incorrect fuel pressure and a bad o2 sensor could definately cause that. Does your car have any other problems? Overheating, overcooling, yatta yatta..

Also, scan the ECM for codes, see if it's saying anything.

 

Fortunantly this is the only problem. Im going to check for codes tomorrow.

 

 

no codes, plugs are all black. Too rich? So ho2 do I control the fuel delivery. Its not a adjustable fpr. Any ideas?

 

I had the exact same problem except I got a code 42. I couldn't figure it out so I took it to a mechanic and it ended up being my computer. I think that you should check that. My car runs great now. I can punch it and burn out again. I havn't been able to do that in a long time.

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88 iroc
LB9 305 tpi
k&N, flowmaster, ADS chip
160* thermostat
home made ram air
removed smog pump
TB bypass
ASCD big block hood

AIM - chris1roc

 

Removed cat, fixed problem. Replaced cat w/Flowmaster. Found lost power, and a fat *** rumble!

 

wow it was the cat??

 

Hmm, PLugged Cat casuing rich condition ?


or....

Plugged cat Was a seperate problem and you still have a rich Condition


Check your plugs again, they still Black ?


I fail to see how a plugged cat would cause that condition, But I have Been wrong Before




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype