I have a 92 Mazda Protege DX. The engine (upon acceleration- giving gas at any time) stumbles or lacks power.
I have googled this problem and unfortunately there is no answer given by anyone (everyone seems stumped). They mention vaccum leaks, fuel filters, sensors, etc (google the answers if you will).
We replaced the spark plugs, and fuel filter- the performance improved, but the problem is not solved (it had a full tune-up not long before).
I use 87 octane.
The problem only occurs once the engine hits normal operating temp- never before. It starts fine, etc. when cold. Once it begins acting up, not accelerating, and stauling at stop (once hot) and is shut off it will not start/idle correctly until the engine is cold (1-2 hours later).
By these symptoms it does not seem to be the fuel pump (would be more often or always), fuel injectors (same), the fuel filter (changed), plugs, plug wires or distributer (relatively new and did not cause problems when they were changed)
I have not tested sensors or for vaccum leaks, but judging by what others have said these will probably help (like all other ideas and replacements), but will not solve the problem- will do them anyway.
Does anyone else out there with experience have any real ideas that I have probably not heard of when googling this problem. Typically, I hear, PCM, ECR, TPS, fuel filter, plugs or other ignition symptom (is definitely not my case), fule pump (I'd think would do all the time), timing (again- would think all the time, not just when hot), fuel injectectors (wouldn't these also perform badly when cold?), etc.
I emphasize that it is ABSOLUTE that if the car sits for 1-2 hours it will start, run, and accelarate fine until the engine temp operating range reaches normal! Once it reaches normal it will not accelratwe if the gas peddle is pushed, but it seems fine when held steady.

Any serious or experienced suggestion?
Blessings,
J Ranck

 

i would check the EGR valve, check for vacuum leaks in all lines, and check the IAC valve. this would be a start. the only thing that i could think of other than a valve or vacuum line would be low engine compression due to a warped head or old rings.

 

check your firing order and make sure all plugs are firing on the intake stroke not the exhast. find that vacuum leak also most of the time its that stupid intake gasket.