Service Engine Soon light is ON

[Alfonso Gomez]

Today, my 87 Coupe started fine and I drove to a couple of places. As I left the pharmacy, going about 20 mph, the engine died. So, I shifted into neutral (auto tranny) and started the car. It started right away but the Service Engine Soon lighted up.

The car functioned OK but the light did not go out. So, when I got home I shut the engine, jumped terminals A & B in the ALDL to see if there were any codes stored. The code I got was 33 which means something wrong in the MAF sensor circuit. All connectors were tight at the relays and the MAF sensor. I removed the MAF connector anyway and sprayed contact cleaner at both ends, let them dry and reconnected them.

Started the car and it would not idle unless I kept the engine at about 1,200 RPMs for 30 seconds or so, then it idled at 600-700 RPMs. I noticed the engine surging at these RPMs.

Can it be the burn-off relay or the power relay? Or is it the MAF sensor gone bad? The sensor and the relays were replaced on 7/31/2001 and the ECM on 03/14/2003. The IAC was replaced three weeks ago, when I cleaned the Throttle Body. The TPS was adjusted at .54 v.

Any advice will be appreciated.

 

[RedRagTop]

For me it was the relays mounted behind the battery. You appear to have already changed them recently so...

 

[Mart]

Check to see if there are any bare wires going into the relay connection, this same thing happened to 2 of the relay connections on my 86,

The insulation shrinks back.

Mart