I've got a 1990 Corvette with 76,000 miles on it. Recentely it developed a problem with the engine surging only when it warms up. When the engine is cold, it idles fine. It also surges when you drive it in 6th gear on a level surface. There are no codes present either.
In an attempt to correct the problem this is what I've done so far.
1) I have the engine a complete tune up (plugs, wires, air filter, etc.)
2) I checked for vacuum leaks (finding two and corrected them).
3) I cleaned the air idle control valve (which was very dirty).
4) I swapped out the ECM on my Corvette with a friend's of mine (his being identical) and that didn't correct the problem either.
5) A service technician I knew said he guaranteed it was the fuel pump so I changed that and $170 later, I've still got the problem.
Other mechanics I've talked to suggested that I change the fuel filter (I don't know if it's ever been changed?) so I intend to do that over the weekend. Another mechanic told me it might be the fuel pressure regulator that I see on top of the engine below the plintim and I don't mine replacing it, but frankly I'm getting tired of the "trial and error" method to fix the problem. And I don't know how hard the fuel pressure regulator is to replace.
Anyone else have any suggestions or had a similar problem?
Thanks,
Randy Wilkinson
It sounds like an intake manifold vac leak. After the engine warms up use a can of spray carb cleaner at all edges of the intake. Use short bursts of the cleaner and see if the RPM changes. If it does you have a vac leak. That means replacing manifold gaskets.
SOURCE: Engine cranks excessively before engine starts,even after warmed
Check your EGR valve make sure that is working properly, if it is then go to the fuel pump, just a cheaper fix to go after the EGR then the fuel pump
SOURCE: 1996 s10 2.2 engine starts but idles rough and will not rev up.
Hi! You must be frustrated by now! your code is marking that the O2 sensor is bad in bank 1. Did you replace the O2 sensor that is located before the catalytic converter? The S10 has an O2 sensor specially made for that cat. its about 30$ That would explain for your blackened spark plugs; your pc on the car is asking for more fuel. GOOD LUCK!!
SOURCE: 1989 Corvette starting and idle problems
i HAVE THE SAME PROBLEM AND TURNED MY IDLE ADJ SCREW DOWN BUT THE IDLE STILL GETS STUCK I ABOUT 900 RPMS AND I HAVE TO TAP THE GAS PEDDLE DOWN TO GET THE IDLE TO DROP TO 600 CAR IN DRIVE AT A STOP I THINK I HAVE TO CLEAN OUT MY IAC BUT I AM NOT SURE THIS THIS HAPPENNED AFTER I CHANGED MY BAD INJECTORS I RESET THE TPI TO 0.54 VOLTS ALSO DO YOU HAVE ANY IDEAS
SOURCE: pops back through the intake when it is cold runs
This problem can be caused by defective spark plug wires that are cross firing due to voltage leaking to a nearby plug wire as well as a flat camshaft lobe.
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same as above
i have the same problem but mine surges at any rpm, any gear, but acelerates fine with no miss. runs fine till it warms up and goes into closed loop, then starts surging. checked everything i can think of. has 40+ psi fuel pressure, constant good vacuum, cat converter clear, all computer readings are in limits, no codes. it does seem the timing is changing alot when surging, but so is the rpm.
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