Engine miss

[94shodriver]

So... I'm not driving the car or even in the same state, or continent, but...

My 94 MTX 3.2 swap with 40k on a rebuild, almost everything new, has developed a miss while my wife was using it. It started on the freeway after a few days of eventful driving, save for a surging idle on the first start up after removing the car from storage. Apparently the car was missing at part throttle cruise, but not at idle or more throttle, the CEL was flashing, but the tach was responding normally. After one shutdown for a half hour or so, the car ran normal for 20 minutes, after which the symptoms returned. This occurred again, and the missing became more violent. After another shutdown for an hour, it was driven through town for 20 minutes to where it currently is without incident. I had someone pull the codes and they found 539, 10, 214, 528 and 542.

I was chasing a cold idle problem a few months ago and swapped out the DIS and TPS as well as installing a new camshaft position sensor. I put a new coat of heatsink compound on the DIS. The fuel pump was replaced a few thousand miles ago. New plugs and wires were install with the rebuild along with cleaning and flow testing the fuel injectors. I did a cylinder balance test when I replaced the TPS and it passed. Front 60k was done with the rebuild, O2 sensors too.

So far I'm thinking clean the MAF, replace the fuel filter (it's due), and instal a new TPS.

Any other ideas?

TIA

 

[rubydist]

your 94 SHO will not have any 2-digit codes, so the codes listed are suspect. also, codes are listed in numerical order from lowest to highest, then repeated, first for any codes it 'sees' during the koeo test, then for stored codes.

from your symptoms, the most likely candidates seem to be dis, coil pack, tps and/or pcm, but being sure of the codes would help.

 

[94shodriver]

The codes were pulled using a reader. I believe that 10 is a separation code. The only significant codes are 214 and 542. 539 states that the AC was on while the code were being pulled and 528 is from me grounding out the clutch switch so I could start the car without having to depress the clutch.

Is the flashing CEL while symptomatic indicative of any common issues? I searched and could not find anything conclusive.

 

[jayro]

Is the flashing CEL while symptomatic indicative of any common issues? I searched and could not find anything conclusive.

I believe the flashing CEL means that there is a misfire that is currently occuring.

 

[94shodriver]

Is there any way to test a DIS beside replacing it?

 

[rubydist]

fwiw, I have not had good luck using a code reader to pull obd1 codes - they typically will read either current or stored codes, but the ones I have seen do not seem to read both.

however,

214 is for a cid circuit failure - that is the cam sensor. if the cam sensor is dead, then the car will run normally (hard to start, though) but without tach reading. however, I have seen sick cam sensors result in all sorts of poor engine performance. your issue could be a connector/wiring issue or the sensor itself. fortunately, they are not expensive.

542 is the fuel pump secondary circuit, and that is almost always a junk code that gets set if the engine stalls. you can safely disregard this one until you have all other codes eliminated but a remaining problem with performance.