98 tahoe running rough

SOURCE: 1997 chevy truck running rough

Is this a 5.7? They are notorious for intake manifold gasket leaks. When mine did it, the diagnostics blamed it on an ignition misfire also! Replaced the gaskets and it runs smooth!

SOURCE: rough idle

Check or replace the EGR

Harvey N Tawatao

• 3854 Answers
• Posted on Jun 11, 2009

SOURCE: 95 Chevy C-1500 runs rough at idle and during accelleration

Check the vacuum line to the fuel pressure regulator and check to see if the fuel pressure regulator has gone bad. Give the throttle body a good cleaning and the injectors too. Do not use carb cleaner, it's to corrosive for the gaskets used in the throttle body. The other thing too that would cause this is a stuck or bad EGR valve, Try cleaning the EGR valve too since your cleaning the throttle body. Good luck and keep me posted.

SOURCE: 98 blazer 4.3 4x4. runs very rough. scan code

ethanol gas problem. add a can of SEAFOAM to tank of Premium gas. change fuel filter after 100 miles. then add SEAFOAM 3-5000 miles to keep fuel line/system;emissions, and valves clean of ethanol goop and water which is created by this awful ethanol mixture.

SOURCE: running rough, spark plugs, distributor cap, rotor

First thing you need to know is which cylinders are missing. Then, don't forget there is an engine beneath the electronics. Do a quick test with a vacuum gauge and do a compression test. Check the distributor shaft for side play. If everything checks out good, then do electronic component testing. have a code check run (many parts stores do this free) and get a chiltons or haynes manual and follow test procedures in there.
I refrain from giving repair suggestions with problems like yours because people keep changing instead of testing parts. When I work on my vehicles or other peoples cars, I do testing to avoid buying expensive parts that most times won't correct the problem. At this point the most I'd suggest is to clean the mass air flow sensor wires with a Q-tip and carb cleaner...that often helps and is free. If you run into a problem with whatever you find, ask and I'll try to help.
good luck

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