I have a 1988 Chevy Blazer. When I drive between 35 - 40mph up hills or drive it on the highway the engine will start to run very rough and feel like it is losing power. The Check Engine light will then come on and it will run slightly better but still rough.
When it is at this point, with the Engine light on, a black sooty fluid spits out of the exhaust.
I have brought this truck in to the garage on numerous occasions to have this problem looked at by the mechanics always tell me that it seems to be fine and they send me home.
If I drive locally then this is usually a non-issue and seems to be tied in to the accelerator - the further I push the gas pedal the more likely the symptoms are to appear.
When the Engine light is off the truck runs fine.
Any ideas what might be causing this or what I might be able to do to have this issue resolved?
That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.
Regarding warning lights:
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if the coolant temp light comes on, shut off the engine ASAP
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if the oil warning light comes on, shut off the engine ASAP
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if a FLASHING MIL/CEL comes on, shut off the engine ASAP
ASAP means driving to the berm of the highway right now and not waiting for the next exit.
But if the MIL/CEL is not flashing, then it’s not an urgent indicator.
You don’t need to go to AutoZone or any other parts store to get the codes read. This vehicle is an 88, so it’s the old OBDI engine management system.
To retrieve the codes, locate the ALDL connector under the steering column. Insert a jumper between the A and B terminals on the connector. Turn the ignition switch to the RUN position. The Check Engine light will begin to flash out the codes.
The first code that should be displayed is a code 12. This will appear as *-**. Where * is a flash and - is a pause. This code indicates that the computer is in the diagnostic mode, and will flash three times. If there are any other codes, they will follow the code 12. And all other codes will repeat three times also. If there is more than one code, the lowest numbered code will flash three times first. And the next numerically higher code will flash three times and so on.
Tester
My first guess is there may be a bad spot on the throttle position sensor but hopefully the engine code will give a better clue to the trouble.
You need to have the codes read. Some places will read them for FREE.
Ah, this is a big peeve with me: Why don’t cars DISPLAY THE CODES,
instead of merely “waving [a] hand … to get attention”!!! Then we,
the consumers, the owners, the affected, could be in a position to research
the indicated problem (to look up info re code P0123), and not be hostage
to believing what a service station might TELL us is the problem (“You need
to help me with my next four boat payments!”).
Also, what if more than one thing tickles the CHECK ENGINE signalling
–how many codes are stored, or is it only the latest, overriding any
prior one? (I once had a dealer tell me that in fact nothing could be read,
but that NEXT time if it happened he’d read it for free–$50 or so, this time,
for nothing helpful. grrrr)
Presently, I’m with a 1991 Subaru Legacy wgn that all of a sudden (w/181_000 mi)
ran rough and gave the CEL–on, then off; later on steadily. Roughness seemed
to abate when downshifting (auto trans) on upgrades; 50mi return home from
occurrence.
Presently: starts, rough, CEL comes on. … awaiting some advice
prior to seeking service.
Thanks,
–Anon., II
Try replacing the fuel filter…It’s probably located back near the tank…
The engine control computer can go bad and cause this. Yes, it could be something else, but check on prices. The computer is likely to be the cheapest part anyway if there are mostly solid state electronics in there like GM used in the eighties. When it happens disconnect the battery and reboot the computer by reconnecting. Repeat if it doesn’t work. If it fixes it temporarily; it sometimes means that the computer is bad.
quote…Ah, this is a big peeve with me: Why don’t cars DISPLAY THE CODES,
instead of merely “waving [a] hand … to get attention”!!! Then we,
the consumers, the owners, the affected, could be in a position to research
the indicated problem (to look up info re code P0123), and not be hostage
to believing what a service station might TELL us is the problem (“You need
to help me with my next four boat payments!”).
Also, what if more than one thing tickles the CHECK ENGINE signalling
–how many codes are stored, or is it only the latest, overriding any
prior one? (I once had a dealer tell me that in fact nothing could be read,
but that NEXT time if it happened he’d read it for free–$50 or so, this time,
for nothing helpful. grrrr)
Presently, I’m with a 1991 Subaru Legacy wgn that all of a sudden (w/181_000 mi)
ran rough and gave the CEL–on, then off; later on steadily. Roughness seemed
to abate when downshifting (auto trans) on upgrades; 50mi return home from
occurrence.
Presently: starts, rough, CEL comes on. … awaiting some advice
prior to seeking service.
Thanks,
–Anon., II
end quote
Unfortunately, its not that easy. Just because a computer throws a specific code, that doesn’t automaticly mean that that is the problem. It gives us technicians a place to start looking. On pre OBD II vehicles it was even more difficult. You have a scanner which communicates with the computer. The scanner shows different parameters. The person reading the scanner needs to understand those parameters, they need to know what those numbers SHOULD be and if they are not what they should be, he needs to know why. One sensor reading wrong might just be due to another sensor or another component. You cant just read a code and throw a part at it hoping that it cures the problem. What if it doesnt??? You cant charge the customer because you guessed wrong. Most parts warehouses will not take back electrical items so your wrong guess could get very expensive. $50.00 to diagnose your vehicle is not bad at all. Scanners can get expensive. I use a Snap-on MODIS. Its a windows based scanner with a built in lab scope, graphing meter and too many other things to list. After purchasing extra adapters and software, it set me back $9,500.00 Software on this is updated twice a year in April and October at a cost of $1,000.00 EACH upgrade =$2,000.00 a year. BOAT PAYMENT??? NO…
transman