Question about 1994 GMC Sierra

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After driving truck an hour service engine soon light comes on

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  • Crhen May 11, 2010

    Should always post engine option when asking a vehicle service question



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  • GMC Master
  • 752 Answers

Check gas cap make sure its tight,these trigger light a lot.or you could need tuneup.

Posted on Feb 07, 2010


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Posted on Jan 02, 2017

  • 185 Answers

SOURCE: 2004 Nissan Frontier Service Engine Soon light came on

P0321 Ignition/Distributor Engine Speed Input Circuit Range/Performance. P1456 Leak Detected In EVAP Control System. Sounds like a vaccuum leak somewhere. I would clear these codes out and see if they come back first. Then if they do I would check to see if you have a vacuum line loose or broken off. If they codes stay off it would be ok to keep driving the truck, but if they came back I would definately get it looked at.



Posted on Nov 15, 2008

  • 188 Answers

SOURCE: Truck losing power and service engine soon light on

Like to other guy said, give it a tuneup. Also try SEAFOAM to clean carb up of slug. Also check to make sure the butter fly for the choke has not come loose, causing it the choke it down. Failed choke pull-off.

Posted on Feb 02, 2009

  • 1 Answer

SOURCE: service engine soon light comes on sometimes bmw 530i 2003

my service engine ligth came on then it went of

Posted on Apr 02, 2009

  • 414 Answers

SOURCE: "Service engine soon" on highway

This is a hard code meaning there is something wrong scanning the PCM is your only real option.

Posted on Jul 12, 2009

  • 5081 Answers

SOURCE: service engine soon light come on

There are TONS of reasons - the first , and least expensive, step is to read the codes that the onboard computer is throwing. Instead of spending a lot of money on a code reader, or wasting money by going to the dealership, find an AUTOZONE (or, sometimes MERCHANT's will offer a "we'll check your CHECK ENGINE LIGHT for free) and they'll give you a generic read of the code(s).
I say "generic" because the computer DOES throw specific codes; the "we'll do it free" places usually don't have the same kinds of super-readers that the dealerships or high-end repair shops own. But, bear with me for a sec....this may save you some money.
If the generic code says, "O2 sensor"....that's not as specific as you'd like (because there are multiple 02 sensors!)...BUT....if ONE sensor is not functioning properly, its a pretty good bet that the other(s) will be failing soon too, since they were all installed at the same time and all were made by the same company, etc.
The "generic" code WILL tell you enough info as to which sensor is bad (the one in front of the converter vs the one behind the converter) so....if THAT is the code, then simply replace both behind or both "in front". Follow?
Now, where you'll typically get the most common code is for low fuel pressure. If you've never changed your fuel filter...that's a good place to start. The "generic" code will indicate "fuel pressure". If you've never changed the filter....see? BUT, a fuel pressure problem could also be as simple as "loose gas cap"! If your generic code says "fuel pressure", then I'd reset the computer (disconnect the battery for a few minutes and re-connect), and while the battery is disconnected, make sure that the gas cap is tight and the little rubber gasket around the cap is in tact.
Keep in mind....a "check engine light" doesn't mean that your computer is throwing codes CONSTANTLY! It means that the computer sensed something at some point while the scan was running and SOMETHING got its attention. "IF" the fuel cap was loose, for example, just re-tightening it will not reset the "check engine light"! You gotta reset the computer (disconnecting the battery is easiest), THEN the light will be off. If the light returns, then the problem was something other than the gas cap.
Taking your time and doing a little on-line research can save you a ton of money! A 2000 is relatively easy to work on least SOME of the issues...even if you're not a really techie-kinda person. Take the easy and inexpensive shots first....
Hope this helps.

Posted on Oct 12, 2009

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Lack of power

LOTS OF THINGS!... did the CHECK ENGINE light come on? Whenever the 'CHECK ENGINE' (Service Engine Soon) light comes on, the ECU (Engine Control Unit) sets a Diagnostic Trouble Code (DTC). These codes identify the particular engine management system which caused the light to come on.
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Service engine soon light came on after full tune-up

Make sure the gas cap is on tightly. A loose or faulty gas cap can cause an intermittent check engine light. Hope this helped and best wishes.

Aug 18, 2009 | 1995 Chevrolet S-10 CA Edition

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"Service engine soon" on highway

This is a hard code meaning there is something wrong scanning the PCM is your only real option.

Jul 12, 2009 | Chevrolet Silverado 1500 Cars & Trucks

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Service engine soon light

a check engine light or service engine soon just means you are not meeting emissions. definitely not a big deal.
go to autozone and have them do a free scan and get the fault codes.

Also, try this first - disconnect the battery for 1/2 hour and see if it turns the light off. Drive for 10 miles and it may run rough until it relearns your engine controls.
let us know results.

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