Imissed the second page....... change your burnoff relays right behind the battery on the fire wall 15mins-$15 easy cheap o2 sensor if not new replace it cheap easy, the maf should be pulling 4-8 grams per second past it if too high the ecm will try to compenstate by starving the car and lowering the RPM's if its at 9grams or higher change it, also if you know somone who has and extra one you can swap it and see if that changes it. keep in mind mid america has a the ecm for $329.00 but super expensive.
also check the connections to the relays and the connection to the MAF , also with the engine idling, try tapping the MAF sensor with the handle of a 6" screwdriver. I don't mean belt it with a 3 pound hammer, just tap it lightly, if the engine stumbles with ever tap=bad
ECM is the last resort it may be bad and hunting for the idle all on its own but UNLIKELY
hope this helps you bro!!!

 

ment MAF for $329.00 sorry

 

That's what I was thinkin' too there, '84. Ya' don't wanna' hear it after you re-do the entire intake, but I got no clues what else could cause lopin' idle with no codes...

ibelew, did you get a good grease film on the gaskets at re-assembly? Grease film helps seal, AND helps hold the gaskets to the intake runners, when you're puttin' the plenum back in between the [still-loose] left and right intake runners... And the TB passages gotta' match up with the right gasket openings. What a pain that was[:@][:@][:@].

At the same time, you don't wanna' over-torque any bolts in the aluminum either.

 

OK, just finished putting my second set of gaskets in. Still have the erratic idle. If I disconnect the ESCthe idle smooths out. I've got a new MAF sensor, new IACplugs, wires, cap and rotor and two sets of intake gaskets. I'll check out a burn-off relay tomorrow. Where is the MAF power relay located. By the way I plugged a new ECM in with no luck so I returned it. I think I'll go tune my 79 up since it's alot easier to work on. Give me some good advice guys. Thanks.

 

Chevrolet Corvette Check Engine Light
Q. I sure hope you can help me. I have an 1988 Chevrolet Corvette with an L98 engine with 113,000 miles and automatic transmission with little, if any problems mechanically. The check engine light is intermittent. Some days its on and others its off. I have taken it a few mechanics and all say its a wiring problem, probably a short somewhere.

But they are unable to locate. I have noticed when the check engine light is on it is giving me a code with some thing to do with the MAF sensor or the burnout circuit relay. All of that has been changed so its got to be a wire problem.
I noticed a green wire on the drivers side near the engine block and transmission. I have attempted to ground it but is a hot wire. I know a green wire comes from the MAF sensor but unsure where this green wire goes.
I don't know if this is the problem or this needs to be connected somewhere. Do you have any reference material showing wiring locations and if there is any remedies for this? Any help?
Thanks,
Michael
A. Have you tried a dealer? There are a few service bulletins out pertaining to this code and replacement of power and burn off relays with a new design relay.Number: 88-251-8a
Section: 8a
Date: June, 1988
Subject: Intermittent Connection To The ECM
Model And Year: 1988 Chevrolet Passenger Cars And Light Duty Trucks T: All Chevrolet Dealers
A condition may exist in which the female terminals in the connector to the ECM do not make a solid connection to the male pins in the ECM (see illustration). This can result in an intermittent condition, in any circuit operated by the ECM. The Service Manuals direct a check of connections any time an intermittent condition is found, and this may be the cause of some of these conditions.
Visually inspect the terminal using a flashlight, or use a .95 mm pin gauge. The gauge should not pass freely through the female terminal. Do not probe the terminal with anything other than the pin gauge, as probing could damage the terminal. If the female terminal does not grip properly, replace the terminal with P/N 12020757. General directions on wiring repair are shown in Section 8A of the service Manual.
Number: 89-327-6D
Section: 6D
Date: May 1991
Corporate Bulletin No.: 138111
Subject: Intermittent No Start, Long Crank, Stall, Or Engine Surge
Model and Year: 1988-1989 Corvette
Condition:
On the 1988-89 Y Car, the engine may have intermittent no start, long crank times, may start and stall after start, or may have engine surge or rough running. No codes will be set, and no trouble can be found using normal diagnostic procedures.
Cause:
The relay used for production, P/N 14103304, may not conduct enough current to allow the Mass Air Flow (MAF) circuits to operate properly. The relays will test OK.
Correction:
Both the MAF relays (Burn-off and Burn-off control) should be replaced with relay P/N 14089936. This relay is serviced with a bracket, which is used only for 1988, and can be discarded for the 1989 model year. The location of the relays is shown on page 8A-20-9 of the 1988 and 1989 Y Car Service Manual.
Pad is currently available from GMSPO.
The O2 sensor may also be carbon-coated because of this condition. To clear the carbon, apply the parking brake, and allow the engine to warm up to normal operating temperature. Then hold the RPM at 1,800 RPM for three minutes.
I KNOW ITS A LOT TO READ BUT IT WILL HELP YOU UNDER STAND THE PROBLEM A LITTLE BIT BETTER TO COME TO THE SOULUTION
COURTESY OF ALLDATA

 

Hello, wires are good. Installed new burnoff relay with no luck. No vacuum leaks. Idle is still erratic until I pull off the connector to the ESC. Plan on installing a newa new knock sensor tomorrow since it failed the ping test, I think I'll have a spare ESC standing by as a trouble shooting aid. What else do you guys thinkI should check.Thanks.

 

This knock-sensor test failure will have an effect on your timing.

Normally it would retard the timing when a vibration (knock) is detected. You'd have less power. But didn't you before have a code for 'too long retarded timing', or something like that [no signal]???

 

Hello. I had a code 43 that led me to check the knock sensor and it failed the test you recommended. I need to start back probing some pins on the computer. I can't afford to keep throwing parts at it. I still have the erratic idle but not as bad. The car runs great when accelerating but crappy at cruise and idle. Thanks.

 

Does it feel like it's surging at cruising speed? If so, heres something to try...temporarily disconnect the vacuum line going to the EGR valve and plug it with something. You'll need to disconnect it at the EGR solenoid because you won't be able to get your hand under the plenum to reach the egr valve.Take it for a drive and see if it runs any better at cruising speed.

 

Do you have a K&N filter?