Idling at 2200 rpm and speedo&A/C cuts out intermittently

Hesitates horrible when cold.

Wont rev over 4200 rpm at full throttle, but about 80% throttle is better, at 4k plus & full pedal backfires in exhaust.
Has limited power and hesitates bad with minor exhaust backfires at full pedal but about 80% accelerates smoothly till around 4k have to take my foot out of it to shift (less than 50% pedal to make it shift)

Speedo needle just drops off for a while and comes back on intermitently (sometimes no speedo for days straight) AND when speedo cuts out the A/C compressor cuts out!!! (this is VEGAS!!!!) worse part is i bought the car for my elderly mother and it had been perfect for 4 years now this, and she is drivin my car till i can fix EVERYTHING, but i have to keep her in a car with A/C... HELP!


rarely idles below 500 rpm and dies when put into gear

I am thinkin VACUM LEAK?

Checked all vacum connects and changed PCV and the lil grommets on it.

just changed intake manifold gaskets (was leaking coolant, puddled under plenum) and disasembled throttle body n cleaned everything to look like new.

Cleaned up the iac and tested with it unplugged, no change.

next is ECT, seems to run extra cool and i live in VEGAS (i did put an oversized truck radiator in it though it operates at like 140-160 F

TPS figure it could be screwy have to go get my ohm meter from the shop.

EGR think it might be hung open?


SPEEDOMETER also suddenly started cutting out intermittently and A/C cuts out when it does... Electrical?

on my way to buy a OBD I scanner will post code later....




91 bonnevile 3800 90K mint cond.
(old lady owned and meticulously maintained got all records bought at 71K)

12 - diagnostic test working properly

14 - ECT coolant temp sensor low voltage

23 - manifold air temp sensor signal voltage low or high
or TPS error
or mixture control solenoid open or circuit fault

42 - Electronic Spark Circut open or shorted to ground during RUN
or Direct Ignition System fault - bypass circut open or shorted to ground during
engine RUN
or fuel cutoff relay open or shorted to ground



So i figure it is time to start checking wiring for a melted or mangled harness grouping, i suppose. HELP......

Clear the codes and see what comes back. Some may be old and you don't want to chase ghosts that have already been fixed.

those are the codes after i cleared the computer... i think the ECU might be bad. this morning car ran perfect when i left for work.... 3 miles down the road, all the * hit the fan at the same time.... A/C speedo loss of revs and power shifting was less pronounced and more delayed n slugish....

oh an d all these codes and problems started at the same moment on way home from grocery store, i was lucky enought otake the ride,....

old timer i know workd in GM used (buick dealer) said tap the side of the comp caseand see if it starts to bug out, miss, anything n its bad.

any experience, cuz im not to fond of beaing valuable components with sticks...???

pulled ECU today and it is the problem tapped it and the idle started bouncing.

cleared codes again and restarted it runs perfect, except engine light only one code now, a new one.

13 - system O2 lean at cruise or left O2 circuit open.

so grab a new one and slap it in and call it hopefully.

I had a bad alternator that was failing did some of the same things you are having problems with .My alternator wasn't putting out the correct voltage...the voltage should be 13.5 at idle and 14.5 to 14.75 at start up, these cars are voltage sensitive. Also these alternators don't put out enough ampeage at idle GM put off the shelf alternators in these cars. A GM alternator on these cars are rated at 105 amp to 140 amps but realistically put out 35 to 50 amps at idle which is not enough for the electric load of these cars and drains the battery causing them to fail. I also upgrade the charging wire to a 0 size and put on a powermaster alternator to cure these problems hope this helps