1990 Missing and Hesitation
Thread Starter
Racer
Joined: Dec 2004
Posts: 470
Likes: 0
From: Phoenix Arizona
1990 Missing and Hesitation
Stopped at a traffic light, my car began to miss with a heavy lobe and it almost stalls. This occurs after the car begins to warm up to 180* to 200* as soon as I put the car into drive (automatic) the missing intensifies to the point of stall, however it has not stalled, and when I shut off the car it starts immediatly. Not sure if I am getting to much fuel or not enough, also a strong smell from the exhaust after the car has reached normal running temperature.I have searched this forum extensively and checked MAP, IAC connection, vacuum lines, fuel leaks, fuses, plug wires, TB. Have not checked fuel pump and sending unit. New headers and corsica exhaust installed with two cats. I am thinking injectors, original multitec, what is confusing is this occured almost instantly this was not a noticable building problem that I negelected by pretending it did not exist, I drive without the radio on most of the time just to listen to the car. 
Your help is appreciated
Your help is appreciated
Advanced
Joined: Aug 2006
Posts: 56
Likes: 0
From: Frederick Colorado
Stopped at a traffic light, my car began to miss with a heavy lobe and it almost stalls. This occurs after the car begins to warm up to 180* to 200* as soon as I put the car into drive (automatic) the missing intensifies to the point of stall, however it has not stalled, and when I shut off the car it starts immediatly. Not sure if I am getting to much fuel or not enough, also a strong smell from the exhaust after the car has reached normal running temperature.I have searched this forum extensively and checked MAP, IAC connection, vacuum lines, fuel leaks, fuses, plug wires, TB. Have not checked fuel pump and sending unit. New headers and corsica exhaust installed with two cats. I am thinking injectors, original multitec, what is confusing is this occured almost instantly this was not a noticable building problem that I negelected by pretending it did not exist, I drive without the radio on most of the time just to listen to the car.
Your help is appreciated
Your help is appreciated
Le Mans Master
Joined: Aug 2005
Posts: 5,002
Likes: 5
From: No Opti Here Tn
St. Jude Donor '06
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
A common problem with spark modules with some age is they provide a weak spark when they get to operating temperature. Engine hot, pull a plug wire and bring a grounded wire close to the plug wire. You should easily have a 1/2 inch spark that is bright and snappy. You can even compare the spark when the engine is cold. Weak spark also makes for hard hot starting.
Instructor
Joined: Nov 2005
Posts: 210
Likes: 0
From: fall river MA
i had the same exact problem. ohm the injectors and i'm sure you will find a couple of bad ones. 16 to 17 ohms cold. my 91 has only 56000 miles and had 2 bad injectors. from doing research and asking ques. on this forum i found out that the multec injectors are pretty much junk.
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Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
I am not sure Arizona requires an emission test when you renew your license plates. Your car may be running a little rich due to having the 24 pounders instead of the 22s. FYI only.
Intermediate
Joined: Dec 2006
Posts: 44
Likes: 0
From: Bay Area CA
I had almost the exact same problem. Ohm out your injectors, hot and cold. They are probably going bad, resulting in a lean condition. Lean = hot. This may be damaging your cats and causing the bad smell. Are the cats rattling? Put your hand near the exhaust tips. Weak pressure? If so, your cats are failing by clogging up. Another symptom of the lean = hot condition are red hot pre cats (check em in the evening or at night after the car is at operating temp).
