Car is misfiring while accelerating ??
Thread Starter
Instructor
Joined: Feb 2007
Posts: 154
Likes: 0
From: Brunswick Ohio
Car is misfiring while accelerating ??
Car just started doing this. Car runs fine at cruising and idling, just when depressing the gas pedal, it stumbles and misses trying to accel.
Before I start digging into it, what are common problems I should look to first. Car is an 85 with 101k miles on it. Thanks.
Before I start digging into it, what are common problems I should look to first. Car is an 85 with 101k miles on it. Thanks.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Could be a ton of things, needs a tune up including new wires, dirty TB, TPS on the way out. Do you have the FSM? Things listed above. Mine turned out to be a bad injector pig tail. I doubt it's the ignition module though, if they're on the way out they usually make the engine run crappy (or not at all) in all RPM ranges as soon as they get hot.
Tools needed.
Fuel pressure guage
Digital Voltage ohm meter
Noid light.
Tools needed.
Fuel pressure guage
Digital Voltage ohm meter
Noid light.
Drifting
Joined: Apr 2007
Posts: 1,339
Likes: 2
From: port charlotte fl
Mine started to miss quite badly at WOT above 4000rpm.At partial throttle openings it would rev to 5000 with no miss!It had an expensive DYNA_MOD high performance module in there.Changed it for a cheap NAPA unit,no more miss.
Team Owner
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
sounds like they're toast. If that doesnt fix it i'd check out the MAF system. On my '85 the MAF module had a few broken solder joints and caused it to misfire. Easy fix if you can get it out of there without too much hassle. Replace the spark plug wires first though, probably burned up.
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Thread Starter
Instructor
Joined: Feb 2007
Posts: 154
Likes: 0
From: Brunswick Ohio
Update, I think it was just a bad tank of gas. Used an off brand from normal, and it started with 12 hours after fill up, had tried Dry Gas to the tank immediatley when it acted up, but didn;t help any at that time. On the way home last night I was down to about half a tank and topped off with my normal station with the 94 I usually run. byt the time I got home it was clearing itself up. Hope thats all it was.
Here is a question thou, if an 85 had a misfire, would the check engine light come one. New cars, 96 and newer with the OBDII computer will lgiht immediatley and stay lit and stored. My light never came on, but not sure on the 85 technology for diagnostics.
Here is a question thou, if an 85 had a misfire, would the check engine light come one. New cars, 96 and newer with the OBDII computer will lgiht immediatley and stay lit and stored. My light never came on, but not sure on the 85 technology for diagnostics.
