Timbo
New member
I've had a '99 Sonoma for three years (2WD, 4.3L engine, automatic). Currently 118K on the clock and for the last year has been offering me some momentary lag on acceleration. I've had a P0300 code fire numerous times, and I've tried various fixes to the problem, but last week things really got bad. Headed to work, -12F, and a half mile to go the engine really started to cough, "clink" (minor backfire), and just barely accelerate from stop. Shifting into neutral evened it out some but it was still missing a bit. Drop it into gear and holy cow, did it ever get rough. Check Engine light alternated between flashing and solid on, and after work I managed to limp it into Autozone to check the code. Again, P0300 (random engine misfire), and the counter person thought it was most likely an ignition control module. I had already replaced the coil pack, cap and rotor, and plugs and wires. I was starting to suspect a failed injector spider, crankshaft position sensor or worse - slipped timing chain.
Well, the next day I managed to get it into a real mechanic who found out the rotor I had installed two years ago had somehow stripped the mount and was wobbly on the shaft, causing serious arcing and misfire. A new cap and rotor and it runs like new. I would have never thought to go back to that and replace it, since I considered it recently new.
Take home message: sometimes asking a professional to run a full diagnostic without a lot of background info allows them to look at all the things you had already done, and maybe find something you did wrong or replaced with faulty equipment. I'm not so proud I can't admit I might have bought cheap parts or installed the part incorrectly. Not to mention the rotor and cap is a lot cheaper than the other things I was prepared to replace.
Well, the next day I managed to get it into a real mechanic who found out the rotor I had installed two years ago had somehow stripped the mount and was wobbly on the shaft, causing serious arcing and misfire. A new cap and rotor and it runs like new. I would have never thought to go back to that and replace it, since I considered it recently new.
Take home message: sometimes asking a professional to run a full diagnostic without a lot of background info allows them to look at all the things you had already done, and maybe find something you did wrong or replaced with faulty equipment. I'm not so proud I can't admit I might have bought cheap parts or installed the part incorrectly. Not to mention the rotor and cap is a lot cheaper than the other things I was prepared to replace.