Cat or Injectors?

[Guest]

Guy's

it's the newbie again......just took the 90 Reatta for the first test run after my brake rebuild and everything is working great as far as stopping goes! After about 20 minutes of driving at 55-60 mph the "Service Engine" light comes on......all gauges show good temp, oil pressure and voltage.......drop speed back to about 50 mph and light goes out?!?!

Here is where it gets strange......after about 30 minutes more of driving the engine suddenly began to "miss" and had a dramatic loss of power.....like running on 4 cyl instead of 6.....prior to that she was smooth and responsive. Once the "miss" started an exhaust leak seamed to occurr in the area of the cat. converter?!?!?

This is what I'm thinking......possibly a clogged cat or fuel injector? I had a cat in another vehicle years ago that "clogged" suddenly while driving and that car had a huge loss of power similar to this one?!?! I also had another Buick V6 that the developed injector "clogs" due to bad gas and it seemed similar? The exhaust leak has me stumped as to why this would "suddenly" occur at the moment of power loss unless the cat clogged and caused a "blow" out at some weak rusted area?

Any thoughts or suggestions????????

Car has 120,000 miles......installed new plugs, wires (after the miss began but didn't help). Car had been setting about 2 years when I purchased it and had about 3/8 tank of gas that I treated with STP water remover/fuel injector cleaner and filled tank with new fuel (89 octane).

Jeff

[ductune]

What codes are set?

[Guest]

No Codes!

Saw a similar post about rough idle and loss of power.......could it be the coils instead of the cat or injectors?!?!?

You guys rock......I'll let you know if the Delco (Delphi) coils fix the problem......got a buddy in the junk yard business that should have these coils to swap out!

[Guest wally888]

My 1st. 89 displayed the SES light a few times while driving. Was always in the heat of summer, 99*> but always went out after I slowed down. I figured it was overheated CAT (no basis for my figuring) and ignored for several years, then sold.

[Guest]

Still having rough idle problems and trouble finding an ignition module from a local scrap yard!

Replaced O2 & Cat, since car had 122K figured I should bite the bullet on these items and hope it will pass emissions testing!

Harmonic balancer went the other day after sitting several days in the garage...as did the water pump bearing and alternator bearings....now I'm getting the dreaded "Electrical Problem" message on the IP frequently!!! I think the curse of my old black "sitter" Corvette has come back to haunt me....something went bad on that car everytime you touched the key!

So far I'm up to $1000 more than I paid for the car and it still isn't running right.....gotta send a check to Finn soon for some body parts but hoping to get the car road worthy and pass all inspections before jumping into body work!

Boy it feels better to vent!

[Guest imported_dantm4]

Probably not the problem, but out of curiosity, did you clean your IAC (idle air control)?

-Dan

90' Black/Tan Coupe

[jimustanguitar]

I had a bad oxygen sensor that was speed sensitive, it made the engine almost die while breaking and whudder unhealthily while accellerating quickly. You might check into the o2 sensor, there are ways that you can check one while it is on a vehicle, it is supposed to measure a certain resistance on a multimeter, your local autozone probably has the procedure in their computer system if you ask them.

[2seater]

You can check the operation of the O2 sensor right from the comfort of the drivers seat. Simply access the diagnostics built into the car and you can watch what the O2 sensor is doing while driving. Once you get used to entering and exiting diagnostics you can do it with one hand while driving. Not that they don't go bad, they do, or they get sluggish, but they usually do not cause dramatic driveabilty problems, just poor fuel economy, although it is possible if it is radically off or dead.

[2seater]

You should probably change the fuel filter at the very least. Depending on how, or if, the fuel was treated before storage, it could be clogging the filter and/or the sock on the fuel pump. It would not be unusual for stuff stirred up after a long idle period to cause all sorts of problems.

[Guest kennyw]

bring up the gages screen. When you see the [now I'm getting the dreaded "Electrical Problem], check the oil pressure guage. It is probably toped out at 155......This will cause the yellow [Electrical Problem] to show it's ulgy face. The fix is a new oil pressure sending unit. About $35...Ken

[bigrog]

ok, the story is getting a little confusing. refresh me....... I should be online here a few times this weekend.

[Guest]

Finally.......I broke down and bought a NEW Ignition Module and Coil Pack from the "PEP BOYS"........(I know why their peppy, now!!!) Set me back almost $250 but the good news is the car is running smooooooooth as silk!

Cleaned that IAC thingy too........O2 sensor is new as is the CAT back exhaust with a new MAGNAFLOW muffler and this baby sounds sweet!

Still having that "electrical problem" pop up on the display and will try the oil sending unit someone mentioned.........YOU GUYS ROCK!

TO DO's.....gotta change the fuel filter & tranny filter this week!

Thanks again guys for your help!

[Guest imported_dantm4]

Out of curiosity - which set of coils did you get? Delco or magnavox? (3 separate coils that are somewhat rounded, or one big rectangle box) Just curious.

-Dan