I bought my dream car off ebay in nov. it's a 91 rs convertible, looks identical to drews convertible. anyways, it was a repo from missouri and the guy i bought it off of got it at an auction and just turned around and resold it on ebay, didn't do anything to it. the ad was, "Rode hard, and put away wet". now that the weather is getting nicer i'm finally able to start working on it after sitting all winter. it had a bunch of little stuff wrong with it, and i'm finally getting it all together. it ran real ruff and back fired, so i thought if i just change the plugs, wires, cap, rotor, air filter, pvc valve, breather, that it would run good. guess what after spending all day doing this, and it was a ***** changing the plugs, on this 305 tbi, nothing like my 89 rs 2.8. i drove it around a little and it's still running real ruff and back firing. before though it stunk real bad from the exhaust but i noticed that it really didn't stink anymore. now, my problem is what could be wrong with it? i want so bad to get it done so i can enjoy it, expecially with the nice weather lately. i would be truely grateful to anyone who can assist me in doing this. if you have any questions that may help you help me out, feel free to ask. thank you in advance guys, and/or gals.

 

Check to see if any of the plug wires are crossed.

 

Check the timing with a timing light to see if it is still in a reasonable range. If the previous owner had tried to adjust the timing by sound, or by rpms or some method other than with a timing light, it is very possible your spark distribution is off.

Look hard for vacuum leaks. Check out all the vacuum lines for cracks, make sure the ends still seal well on their fittings. Old vacuum lines can get so hard and brittle that even though they look like they are properly in place they don't have the flexibility to create a proper seal.

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89 IROC with lots o' stuff

-=ICON Motorsports=-

 

is it setting any codes? if not, replace the bulb, maybe it's burnt out or someone removed it. that will direct you somewhere or rule out a lot of things!

 

If your exhaust stinks, it's either running rich or lean. I'm not the greatest at diagnosing fuel probs though. Someone know more about this than me?

 

it may be possible since it was a repo that the person that had it put something like sugar or dirt in the gas tank before he had it repo'd since he probably expected it. or was just a big enough you know that someone did this to him. basicly a good idea is to check to see if it is running lean. that would be my first guess.

 

Maybe replace the O2 sensor, that thing can cause a ton of problems. Checking for vacuum leaks would be great too, I had this stupid throttle body gasket with a hole in it that has been screwing me over forever and I finally found out this week. Change all the filters and the oil/trans fluid. Change the blinker fluid =p

 

22,

If the car has more than 30,000 miles, it might be a good idea to replace the oxygen sensor. Mixture control is reliant on teh accuracy of this sensor, and the symptoms you are having sound like mostly a mixture problem. If it doesn't cure all your problems, it should at least be better. The service interval for an O2 sensor is supposed to be 30,000 miles, but it raely gets done that often.

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

 

I couldn't agree more (and I GOTTA learn to type faster!)

If "great minds think alike", then the opposite is probably true as well. If I were you, I'd be concerned about my mental well-being....

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

 

If it backfires out the exhaust when you lift off the gas possibly the air diverter solnoid is bad, this is supposed to blow off the air from the smog pump under decel.