c5 hesitation and surging

[jamesgwinn]

I have a 1999 corvette and having problems with hesitation and surging on acceleration. It does not make any difference if the car is cold or hot. There are no dtc code stored. please help.

[basballny2]

MAF

[c5z28]

2nd the maf, pop the hood and give the maf a thump with your hand if it freaks out you have your problem. Probably can check the air sensor that connects to the air box to see if the sensor and hook up is clean.

[Spaz]

take your MAF out and squirt it with some maf cleaner... also check oyur air filer... also when was the last time you had your fuel filter changed???

[Wes1999]

Gentlemen;
I'm a brand-new member here with a 1999 C5-Hardtop, 83,000-miles, manual trans. For years I've experienced hesitation, bucking, deceleration, drop-out of performance when accelerating. I was told by an experienced technician that cylinder carbon build-up due to the LS1 cool running engine will get hot and continue to burn causing pre-ignition which is then detected by the oxygen sensors and the computer wants to retard the engine during acceleration. I've tried a new fuel filter, plugs and wires, cleaning the Mass Flow Sensor & Throttle Plate, BG-44K fuel-additive & carbon-cleaner & I just ordered the OTC Fuel injection pneumatic container and am waiting to clean my injectors this week. I have looked for vacuum leaks at fittings and hoses with starting-fluid to see if the engine would race. Nothing has worked, but..................keep reading....................the $7-dollar improvement. I used a tube of dielectric-grease on the electrical pin connectors from the Mass-Flow Intake, throttle connectors, dual 8-pin connectors to the fuel injectors on each side of the intake manifold and God be praised, IMPROVED PERFORMANCE, 95% CORRECTION & IMPROVEMENT. Now I want to un-clip the connections to the fuel injectors and dab some grease on them and see about the remaining 5% improvement. I just guess heat and oxidation de-grade the efficiency of the electrical connections and create this problem. So have at it. A quick and inexpensive remedy. Wes

[pajeff02]

Interesting. Have not heard of any issues with the electrical connections. Usually it is a dirty or bad MAF that causes the problems you described. Easiest way to test for a bad MAF is to simply unplug it. This forces the PCM into speed density mode and rather than measuring airflow, it estimates it based upon feedback from the MAP sensor and engine rpm. If the stumble and hesitation go away you know the MAF is the issue. Any chance the pins were bent and when you reconnected it that everything plugged back in properly?

[Wes1999]

I unplugged the MAS last night and drove my 1999 C5 this morning with no problems. How does not having the MAS affect mileage and performance. I saw a BWD #29008, MAS on sale at Advanced Auto parts for $110.99, is that a good solution? I've cleaned my MAS in the past and still had the hesitation and bucking on WOT and acceleration. My previous thread on the dielectric grease was for galvanic metal corrosion and did improve some aspects.

[pajeff02]

Your best bet is a GM replacement MAF which you can order and have delivered to your door from GM Parts Direct.

[pajeff02]

You can delete the MAF, however, you also need to change your PCM's tune to speed density. Simply running the car without the MAF is only a band-aide solution and not a permanent fix.